Teams still embroiled in the dramatic battles, such as in the tight National League Central and American League Wild Card races, made things more intense.
The jockeying for position in the AL Wild Card race started in the East on Sunday, when the Orioles kicked things off with a 3-1 win over the Blue Jays, which pulled them within 2 1/2 games of an AL Wild Card slot. Later on, in the last game of the day, New York lost to Boston to fall a half-game behind Baltimore.
The Indians, meanwhile, beat the White Sox to polish off a four-game sweep and now sit a mere half-game behind Wild Card leaders Texas and Tampa Bay, who are tied for the top two slots. With the Rangers and Rays opening a four-game series, the Indians can overtake Monday's loser for the second Wild Card spot with a victory.
"I think just the way we're playing right now is really the highlight of everything," Indians outfielder Nick Swisher said. "We've got a chance to make it to the playoffs."
Think it's clear-cut? Think again.
The Tigers, at least, lent some clarity to the AL playoff picture with a victory over Kansas City. Max Scherzer took a no-decision on Sunday in his fifth attempt at earning his 20th victory, but he struck out 12 batters and Alex Avila homered twice to lead Detroit to a 3-2 victory.
The Royals -- right in the thick of the Wild Card hunt themselves -- dropped to 3 1/2 games behind Texas and Tampa Bay, and they're a half-game behind the Yankees.
"Every loss is tough, right now," Royals outfielder Alex Gordon said. "We had plenty of chances to win it, and [starter Jeremy] Guthrie pitched a heck of a game. He gave up long balls, and that was pretty much it. But he pitched well enough to win the game. That's what our offense needs to do."
The action was just as compelling in the National League. The Pirates got a clutch single from veteran Justin Morneau to lift them to a 3-2 win over the Cubs and a half-game lead over the Cardinals in the NL Central. St. Louis then routed Seattle to keep pace.
The Pirates and Cardinals can both fall back to a Wild Card position if they don't pull out the division title, but Washington continues to make that race interesting. The Nationals got 18 hits in an 11-2 victory over Philadelphia on Sunday, including the 26th straight game in which Denard Span has hit safely.
"It feels good, but then again, I'll trade all those wins in for a spot in the playoffs," Nationals starter Jordan Zimmermann said after notching his 18th victory. "That's the only thing that matters right now. We're playing good ball and scoring some runs, so it's definitely fun."
Washington's win -- coupled with a 6-5 Reds loss in Milwaukee -- means the Nats sit just 4 1/2 games back of the second Wild Card spot in the NL.
The Braves, trying for the best record in the NL, fell short in a 4-0 loss to the Padres on Sunday. Despite the loss, Atlanta maintains a 10-game cushion on Washington in the East and can clinch a postseason berth early this week. The two teams play each other in a three-game set starting Monday in Washington.
Back in the AL, Oakland pulled off a stunning three-game sweep of Texas in Arlington later in the day. The A's are now 88-61 and cruising back to a second straight October appearance with a Magic Number of eight.
The night game showed off the Red Sox, who have vaulted into the best record in all of baseball. They beat the Yankees and lowered their Magic Number to four.
"We're doing everything," David Ortiz said. "We're pitching well, we're playing good defense, we're hitting. Hopefully it continues like that."
When the Pulse of the Postseason fires up the engines again Monday, several teams will be starting series that could bring champagne parties in the clubhouse to celebrate postseason berths. No one can clinch outright on Monday, but several can get that much closer.
The Dodgers' Magic Number is at four and they can wrap up the NL West simply by splitting a four-game series against the second-place D-backs in Arizona. Los Angeles needs to get healthier, with stars Yasiel Puig, Carl Crawford, Hanley Ramirez and Andre Ethier all a bit banged up. But their division lead is more than healthy, despite losing three of four to the rival Giants at home.
Also at four is the Braves' Magic Numbers in the NL East, and, as coincidence would have it, their first three games of the week will come against the second-place Nationals. Win two of three in Washington, the defending NL East champs, and the division will fall.
"We've gone through sometimes some valleys offensively, and then out of nowhere all of a sudden we run off 14 straight or a good seven in a row or something like that and swing the bats really well," Atlanta manager Fredi Gonzalez said. "Looking into the next few weeks, that's what we're looking for, getting back to swinging the bats and scoring some runs offensively."
The A's in the AL West, Tigers in the AL Central and Red Sox in the AL East all have single-digit Magic Numbers, so all three have a shot at clinching this week.
Otherwise, the Wild Cards are appropriately, well, wild.
"We need to at least send a message to them these next three days that we're better than them," Washington manager Davey Johnson said of the Braves. "I always believed we're better than them."
Meanwhile, beginning Monday in the AL, the Rangers and Rays start a four-game series against each other and several of the other teams in the mix play each other later in the week.
"I just know we need to go out and take care of business. If we go out and handle our business, we won't have to worry about anybody else," Rays outfielder Wil Myers said. "It's not like we're not paying attention to what else is going on. We understand what's going on in other games, but we just need to go out and focus on our business and take care of it."
So, starting Monday, prepare to be thrilled while the final two weeks begin to unfold on the field as the Pulse of the Postseason beats on.
Monday's key games to watch (all times ET)
Braves (Minor, 13-7) at Nationals (Haren, 9-13), 7:05 p.m. Preview >
Padres (Cashner, 9-8) at Pirates (Burnett, 8-10), 7:05 p.m. Preview >
Mariners (Saunders, 11-14) at Tigers (Porcello, 12-8), 7:08 p.m. Preview >
Rangers (Garza, 9-5) at Rays (Cobb, 8-3), 7:10 p.m. Preview >
Reds (Cueto, 4-2) at Astros (Bedard, 4-10), 8:10 p.m. Preview >
Indians (Kazmir, 8-8) at Royals (Shields, 11-9), 8:10 p.m. Preview >
Cardinals (Lynn, 13-10) at Rockies (McHugh, 0-2), 8:40 p.m. Preview >
Dodgers (Ryu, 13-6) at D-backs (Cahill, 6-10), 9:40 p.m. Preview >
Angels (Wilson, 16-6) at Athletics (Gray, 3-3), 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/Cardinals
Division Series: Wild Card at Braves | Dodgers at Pirates/Cardinals
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