Then the Red Sox followed suit, entering the October tournament by clinching a postseason spot with a 3-1 win at Fenway Park over the Orioles, leaving them on the cusp of the AL East title, too.
As the Pulse of the Postseason pounded onward Thursday, the AL Wild Card remains a jumble with a bow on top again, Texas and Tampa Bay tied with four other teams within 3 1/2 games. It was a day when hearts were lifted from Pittsburgh to Detroit, and from Cleveland to Washington.
But no contenders could be more content than the Dodgers and the Red Sox on this night.
L.A. wrapped up its first NL West title since going back-to-back in 2008 and '09, besting the D-backs on a solo homer by A.J. Ellis in the eighth inning and a perfect ninth inning for Kenley Jansen.
Boston made it a daily double of teams making their October dreams come true, riding a gem of a two-hit complete game by John Lackey. But the club took a businesslike approach to its celebration, the AL East title yet to be officially clinched.
"We're going to hold off the party for a little bit," Lackey said after shutting down the O's and opening up the door to the postseason.
Following a breathless Wednesday, Thursday brought more of the same drama that makes the September stretch run special.
The day began with a test of the Pirates' will to stay on course following a gut-wrenching loss the night before. The Jolly Roger being raised into the Alleghany River breeze says the Bucs passed this test with flying colors.
Pedro Alvarez ignited a fourth-inning outburst with his 34th homer of the season, tying him for the NL lead. Rookie Gerrit Cole struck out 12 and combined with three relievers in a 10-1 win. And perhaps the Pirates' desire to go all the way this year was seen in the way catcher Tony Sanchez went head over heels into the Padres' dugout for an out late in the blowout.
"I've waited my entire life to kamikaze into a dugout like that," Sanchez said in a postgame interview on the field at PNC Park.
The Pirates are back to one full game ahead of Cincinnati atop the NL Wild Card race, with the Reds coming to PNC Park for a weekend set, and they're back to just one game behind the Cardinals in the division race. Pittsburgh's magic number to clinch that playoff spot 20 years in the waiting stands at four.
In Detroit, the situation for the home team was a little different, with the defending AL champions holding a six-game lead in the AL Central entering Thursday's game. Thanks to a 5-4 comeback win over Seattle, the Tigers cut their magic number to win the division down to four.
Prince Fielder was the difference-maker in Detroit, driving home the tying run with an opposite-field flare, and scoring the go-ahead run going first to third and being called safe on a disputed call.
And, well, he even got into a fan's nachos. The guy was all over the place.
And that was only the beginning of a day when the Pulse of the Postseason is ticking around the clock.
Next up, a couple of teams with a postseason berth in their sights took the fields in afternoon games out west.
In Phoenix, Hanley Ramirez had a huge game in his return to health, going 4-for-5 with two homers. But it was A.J. Ellis' drive in the eighth that did in the D-backs, finishing off the Dodgers' NL West quest and starting the first celebration of September that leads to a spot in October.
"That's easily the biggest home run of my life" Ellis said in a postgame interview on the field. "That felt amazing. To do it on this stage in this game and for this team, it was really special."
With that, Ellis headed into the clubhouse, where the champagne was flowing and L.A. was celebrating a title.
The party went out to the famous pool at Chase Field, and that wasn't necessarily cool with the hosts of the final showdown between division rivals who became particularly bitter at times this season.
"I doubt the New York Yankees would do something like that," D-backs veteran Willie Bloomquist said.
Another NL West venue had a contending team hoping to get closer to October, and the Cardinals battled with the Rockies, knotted up into the late innings on a ninth-inning homer by Todd Helton. The teams played into the 15th before a Corey Dickerson triple ended it, setting off a celebration for the Rockies, 7-6 winners, and deferred any potential Cardinals celebration into the weekend.
As night games arrived, the Nationals continued to fend off elimination with a 3-2 win over Miami, moving to five games out in the NL Wild Card race, and the rest of the action took place in the AL.
While the Red Sox were doing their thing, the Rangers emphatically shook off Wednesday's stunning extra-innings loss at St. Petersburg by routing the Rays, 8-2, behind homers from Mitch Moreland, Elvis Andrus, Alex Rios and Geovany Soto. The win pulled Texas back into a tie atop the American League Wild Card race with Tampa Bay.
Moments before Texas sealed its win, the Indians walked off with a 2-1, 11-inning win over the Astros on Matt Carson's bases-loaded single with two outs. The victory -- fueled by Ubaldo Jimenez's seven strong frames and four scoreless innings of relief -- kept Cleveland a half-game out of the second AL Wild Card spot.
In Toronto, the Yankees couldn't build on the momentum of Wednesday's come-from-behind win, dropping a 6-2 decision to the Blue Jays that dealt their playoff hopes a blow. New York stands a half-game behind idle Kansas City, which is the third team in line in the Wild Card race.
The finale of the night was in Oakland, where the swinging A's finished off another homer demonstration with a two-run shot by Coco Crisp that sealed an 8-6 win. That drops their Magic Number to four in the AL West, and three for a postseason spot.
* * *
When the Pulse of the Postseason picks up again Friday, two teams have secured their spots in the tournament, and the Braves are the next team in line to possibly earn the right to play in October.
There is a showdown between division foes and a pair of Wild Card tussles on the slate as well, so there's plenty more September stretch-run fun in store.
Atlanta will open a weekend series at Wrigley Field against the Cubs needing just one more victory to clinch a tie for the NL East title, hoping to join the Dodgers and Red Sox, who clinched their postseason spots Thursday.
A Braves win Friday combined with a Nationals loss to the Marlins later in the day would clinch the division outright for the Braves. The Cardinals also could clinch at least a tie for a spot if they win at Milwaukee and the red-hot Nationals lose.
Then again, the Nationals also happen to be the hottest of the contending teams, having won 11 of their past 13 games, and they have ace Jordan Zimmermann going for his 19th win of the season against the Marlins.
"It feels good, but then again, I'll trade all those wins in for a spot in the playoffs," Zimmermann said.
Detroit's Max Scherzer will be making a fifth attempt for his 20th win, and the Tigers have an AL Central title in their sights this weekend, taking a magic number of four over the Indians into their opener against the White Sox.
The A's are just as close to a second straight AL West title and continue their series against the Twins with a postseason spot in their grasp during their final home series of the season.
And then there are the races that aren't that close to a conclusion, and there will be a trio of weekend matchups that will make a difference.
The NL Central showdown at PNC Park between the host Pirates and the Reds -- Nos. 1 and 2 in the NL Wild Card race -- will feature a marquee pitching matchup, with Bucs lefty Francisco Liriano meeting right-hander Mat Latos. Pittsburgh is ahead by a game heading into what will be the first of six meetings in the last nine games between the two Central clubs.
And it'll be a pair of AL Wild Card showdowns, one in Tampa Bay and one in Kansas City. The Orioles enter their series against the Rays three games behind the shared lead for the two postseason spots, and the Royals take on the Rangers with a gap of three games separating them from their first postseason appearance since 1985.
"This is definitely what they wanted when they threw in another Wild Card," Orioles slugger Chris Davis said. "But we just have to go out there every day and focus on the nine innings in front of us."
The Indians again will have the potential to jump into the Wild Card spot as they host the Astros again, and the Yankees will try to stay in the hunt as they start up with the last team standing in 2012, the Giants.
Friday's key games to watch (all times ET)
Braves (Maholm, 10-10) at Cubs (Baker, 12-9), 2:20 p.m. Preview >
Reds (Latos, 14-6) at Pirates (Liriano, 16-7), 7:05 p.m. Preview >
Astros (Oberholtzer, 4-3) at Indians (McAllister, 8-9), 7:05 p.m. Preview >
Marlins (Turner, 3-7) at Nationals (Zimmermann, 18-8), 7:05 p.m. Preview >
Giants (Lincecum, 10-13) at Yankees (Sabathia, 13-13), 7:05 p.m. Preview >
White Sox (Rienzo, 2-2) at Tigers (Scherzer, 19-3), 7:05 p.m. Preview >
Orioles (Hammel, 7-8) at Rays (Price, 8-8), 7:10 p.m. Preview >
Blue Jays (Rogers, 5-7) at Red Sox (Lester, 14-8), 7:10 p.m. Preview >
Cardinals (Miller, 14-9) at Brewers (Hellweg, 1-4), 8:10 p.m. Preview >
Rangers (Perez, 9-5) at Royals (Santana, 9-9), 8:10 p.m. Preview >
Twins (Albers, 2-3) at A's (Colon, 16-6), 10:05 p.m. Preview >
Dodgers (Volquez, 9-11) at Padres (Erlin, 2-3), 10:10 p.m. Preview >
If the postseason started today ...
Wild Card: Rays at Rangers
Division Series: Wild Card at Red Sox* | Tigers at A's
Wild Card: Reds at Pirates
Division Series: Wild Card at Braves | Dodgers* at Cardinals
* - clinched postseason spot
To calculate a team's magic number, take the number of games it has remaining and add one. Then subtract the difference in the number of losses between that team and its closest pursuer.
A tiebreaker game will be played to determine a division winner, even if the tied clubs are assured of participating in the postseason. If a division championship tiebreaker is necessary, the head-to-head record between the clubs will determine home-field advantage. If the head-to-head record is tied, then division record will be the next tiebreaker.
If two clubs are tied for the two Wild Card berths, home-field advantage will be determined by the head-to-head record between the clubs. If the head-to-head record is tied, then division record will be the next tiebreaker.
• Tiebreaker rules »
2013 postseason schedule
NL Wild Card Game: Oct. 1
AL Wild Card Game: Oct. 2
NL Division Series begin: Oct. 3
AL Division Series begin: Oct. 4
NL Championship Series begins: Oct. 11
AL Championship Series begins: Oct. 12
World Series begins: Oct. 23