The Yankees started the day's action with a 3-2 loss to the Blue Jays, opening the door for the Orioles to tie the Bombers atop the American League East standings.
Baltimore was able to do that with a 4-3 win over the Red Sox, pulling things dead even with four games left to play.
On a night the O's honored Hall of Fame third baseman Brooks Robinson, it was Manny Machado, Baltimore's 20-year-old rookie third baseman who stole the show. Machado got the Orioles on the board in the second inning with an RBI single and hit a go-ahead solo shot in the seventh to secure the win.
"I'm just trying to play the game," Machado said. "Obviously, it's bigger than any other games I've played before. I'm just going to try to go out there and give everything I can to try and help this team win."
However, Machado wasn't the only one coming through in the clutch on Saturday. With the A's down by two to the Mariners in the bottom of the ninth inning, Josh Donaldson belted a game-tying two-run homer before Brandon Moss delivered a walk-off three-run homer in the 10th inning for a 7-4 win, giving Oakland its Major League-leading 14th walk-off victory of the season.
"There's not much better a feeling than that," Moss said. "When you're playing a game as a little kid in the backyard, that's kind of what you dream of doing."
With that A's win and the Angels remaining idle because of a rainout in Texas, Oakland holds a 2 1/2-game lead over the Halos for the second AL Wild Card spot.
In the AL Central, the Tigers increased their lead in the division to two games after they picked up a 6-4 win over the Twins and the White Sox fell, 10-4, to Tampa Bay. That win kept the Rays three games back of the A's for the final AL playoff spot.
Detroit was led by ace Justin Verlander, who allowed just one run in seven innings, and Triple Crown hopeful Miguel Cabrera, who belted his 43rd home run of the season to tie Texas' Josh Hamilton.
Meanwhile, things got tighter in the race for the second National League Wild Card spot. The Cardinals' lead dropped to just two games over the Dodgers after they took a 6-4 loss to the Nationals in 10 innings and Los Angeles picked up a much-needed 3-0 win over the Rockies.
By beating St. Louis, Washington's magic number to clinch the NL East is one. The Nationals can clinch the division Sunday with a win or a Braves loss.
Led by Matt Kemp, the Dodgers' center fielder belted two solo home runs, with one traveling an estimated 461 feet into the left-field stands. The victory marked the Dodgers' fourth straight win and gave them some life to make the postseason.
"Hopefully, St. Louis keeps losing and we make the playoffs," Kemp said. "We just have to stay within ourselves and we will be there at the end. I feel like we are the most dangerous team in baseball now that our hitting is coming around."
Sunday's key games to watch (all times ET)
Angels (Greinke, 15-5) at Rangers (Darvish, 16-9), 1:05 p.m., Game 1 Preview >
Zack Greinke will begin an important day for the Angels, who sit 2 1/2 games back of the A's for the second AL Wild Card spot. Meanwhile, the Rangers' magic number to clinch the division sits at three.
Yankees (Hughes, 16-13) at Blue Jays (Alvarez, 9-14), 1:07 p.m. Preview >
Tied atop the AL East with the Orioles, the Yankees will turn to Phil Hughes for a much-needed win.
Red Sox (Stewart, 1-3) at Orioles (Saunders, 8-13), 1:35 p.m. Preview >
Joe Saunders takes the hill for the O's as the team looks to take sole possession of first place.
Reds (Cueto, 19-9) at Pirates (Rodriguez, 12-13), 1:35 Preview >
Johnny Cueto looks for his 20th win as the Reds prepare for the postseason.
Mets (Mejia, 1-1) at Braves (Medlen, 9-1), 1:35 p.m. Preview >
Kris Medlen takes the hill for the Braves, who have won 22 straight games he's started.
Tigers (Sanchez, 9-13) at Twins (Hendriks, 1-8), 2:10 p.m. Preview >
The Tigers will look to pad their two-game lead over the White Sox in the AL Central as Anibal Sanchez takes the mound.
Astros (Lyles, 4-12) at Brewers (Fiers, 9-9), 2:10 p.m. Preview >
With an elimination number of one, the Brewers sit four games back of the Cardinals for the final NL playoff spot.
Rays (Price, 19-5) at White Sox (Quintana, 6-5), 2:10 p.m. Preview >
Desperately needing a win to stay in the hunt for the AL Central crown, the White Sox send Jose Quintana to the hill. Meanwhile, the Rays sit three games back of the A's for the final AL playoff spot as David Price looks for his 20th win.
Nationals (Detwiler, 10-7) at Cardinals (Lynn, 17-7), 2:15 p.m. Preview >
The Cardinals are clinging to a two-game lead over the Dodgers for the final NL playoff spot with Lance Lynn set to take the hill.
Mariners (Ramirez, 1-3) at A's (Milone, 13-10), 4:05 p.m. Preview >
The A's will look to pad their 2 1/2-game lead over the Angels for the second AL Wild Card spot.
Giants (Lincecum, 10-15) at Padres (Volquez, 11-11), 4:05 p.m. Preview >
Needing every win they can get, Josh Beckett gets the start for the Dodgers, who sit two games back of the Cards for the second NL Wild Card spot.
Angels (Santana, 9-12) at Rangers (Holland, 11-6), 7:05 p.m., Game 2 Preview >
Ervin Santana gets the nod for the Halos, while Derek Holland takes the hill for the Rangers in the nightcap of the doubleheader.
If the postseason started today ...
Wild Card: A's at Orioles/Yankees
Division Series: Orioles/Yankees at Tigers | Rangers at Wild Card winner
Wild Card: Cardinals at Braves
Division Series: Reds at Giants | Nationals at Wild Card winner
For the 2012 postseason, the team with the better record will play the first two games on the road to start the Division Series.
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 games 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.
2012 postseason schedule
Wild Card playoff games: Friday
Division Series: Oct. 6-12
AL Championship Series: Oct. 13-21
NL Championship Series: Oct. 14-22
World Series: Oct. 24-Nov. 1
Quinn Roberts is a reporter for MLB.com This story was not subject to the approval of Major League Baseball or its clubs.