The Baltimore Orioles moved back into a tie with New York atop the American League after edging the Yankees 5-4 in controversial fashion.
Mark Teixeira, in his return from a strained left calf, was called out at first base at the end of a double play despite a desperate headfirst slide.
Replays, however, indicated the call by umpire Jerry Meals was wrong.
"It was not a bang-bang play. He was safe. He was clearly safe," Yankees manager Joe Girardi said. "You hate to lose a game that way, but he missed it."
Mark Reynolds, Lew Ford and J.J. Hardy homered for the Orioles, who have won 11 of 15 overall and nine of the last 13 against the Yankees. Victory tonight will ensure Baltimore win the season series for the first time since 1997.
But the victory was marred by an injury to right fielder Nick Markakis, who could now miss the playoffs after suffering a broken thumb from a pitch by CC Sabathia.
Markakis has spent his entire seven-year career waiting to be part of a playoff run - but now faces watching the Orioles' efforts from the dugout.
"The timing definitely (stinks) but we got a great group of guys," he said.
"They are going to battle through this. I'll be here for them and I'll be supporting them. I'll be with them and I'll be rooting for them."
Markakis is batting .298 and flourishing since moving to the top of the order. He's the third leadoff hitter the Orioles have lost this season; Brian Roberts and Nolan Reimold have both undergone season-ending surgery.
His loss could not have come at a worse time for the Orioles, who are tied atop the AL East with the Yankees.
Orioles manager Buck Showalter said. "It breaks my heart personally, and for him. I know how much this time of the season means to him."
Elsewhere in the AL, rookie Jurickson Profar drove in the go-ahead run in the 10th inning to help the West-leading Texas Rangers to a 4-2 win against the Tampa Bay Rays.
Chris Sale allowed one run over six innings while Dayan Viciedo, Tyler Flowers and Paul Konerko all went deep in the Central-leading Chicago White Sox's 5-4 victory over the Kansas City Royals.
The Toronto Blue Jays emerged 9-2 winners in a rain-affected game against the Boston Red Sox, the Los Angeles Angels overcame the Detroit Tigers 6-1, the Oakland Athletics prevailed 6-1 against the Seattle Mariners and the Minnesota Twins saw off the Cleveland Indians 3-0.
In the National League, the West-leading Washington Nationals returned to winning ways with a 7-6 triumph over Miami at Nationals Park.
Corey Brown drove in the go-ahead run in the bottom of the 10th inning - a day after the Marlins had dealt the Nats a 9-7 loss which ended their five-game winning streak.
Hanley Ramirez's ninth-inning RBI double spurred the Los Angeles Dodgers to a 3-2 victory over San Francisco which cut the Giants' advantage atop the West to 4.5 games.
Jay Bruce and Brandon Phillips hit solo home runs and Bronson Arroyo gave up one run in seven innings as the Central-leading Cincinnati Reds toppled the Houston Astros 5-1.
Brian McCann clubbed a two-run homer and a two-run double in the Atlanta Braves' 11-3 triumph over the New York Mets, while the first complete game of Jeff Samardzija's career lifted the Chicago Cubs to a 4-3 success against the Pittsburgh Pirates.
In other NL games, the Milwaukee Brewers defeated the St Louis Cardinals 6-3 and the Arizona Diamondbacks beat the San Diego Padres 8-5. The Colorado Rockies' game against the Philadelphia Phillies at Citizens Bank Park was postponed due to rain.