BALTIMORE -- J.P. Arencibia broke open a tight game with a seventh-inning grand slam, and the Toronto Blue Jays beat Baltimore 9-5 Monday night to earn a doubleheader split and drop the Orioles 1½ games out of first place in the AL East.
In the opener, Adam Jones went 4 for 4 with a homer and two RBIs to lead Baltimore to a 4-1 victory. But the Orioles lost a half-game in the standings Monday to the New York Yankees, who won 6-3 at Minnesota.
The Orioles fell behind 4-0 in the nightcap and missed several bases-loaded chances to take the lead before Arencibia connected off Jake Arrieta to give Toronto a 9-4 cushion.
Juan Encarnacion hit his 41st home run for the Blue Jays, who snapped a seven-game skid. Arencibia, who came into the game mired in a 2-for-36 slump, finished with three hits and five RBIs.
Ricky Romero (9-14) allowed four runs, eight hits, four walks and a homer in five-plus innings. But a strong performance by the Toronto bullpen enabled the left-hander to end a 13-game losing streak over 15 starts since June 22.
Encarnacion put the Blue Jays up 2-0 against Wei-Yin Chen (12-10) with a two-run drive in the first inning. In the second, Arencibia hit a sacrifice fly and Anthony Gose added an RBI single.
Robert Andino singled in two runs in the bottom half, but Baltimore left the bases loaded. Nate McLouth hit an opposite-field drive to left in the fifth to get Baltimore to 4-3, but the Orioles again left the bases full.
After Moises Sierra homered for Toronto in the sixth, the Orioles loaded the bases with no outs in their half, bringing many in the crowd of 31,015 to their feet. Brad Lincoln replaced Romero and gave up a first-pitch RBI single to J.J. Hardy before striking out Jones. Chris Davis followed with a fly ball to Gose in left field, and Taylor Teagarden was thrown out at the plate after tagging up.
Baltimore also loaded the bases with no outs in the ninth, but scored only once on a double-play grounder.
In the first game, Orioles rookie Steve Johnson (4-0) allowed three hits over five shutout innings to lower his ERA to 1.62. Half his big league wins have come against Toronto.
Although the Blue Jays got two runners on base in three of the first four innings, Johnson worked out of trouble on each occasion.
Jim Johnson, the fifth Baltimore pitcher, worked the ninth for his major league-best 48th save in 51 opportunities.
Jones' four hits tied a career high. Now in his seventh season, Jones has already set career highs with 32 homers and 101 runs, and the All-Star center fielder needs only three RBIs to eclipse his previous high of 83, set last year.
Jones added a single and a double in the nightcap and has hit safely in 19 of 23 games in September, with six home runs and 13 RBIs.
"Adam relishes competition," Orioles manager Buck Showalter said. "He's obviously had a heck of a year. He's turning into quite a player."
Henderson Alvarez (9-14) gave up four runs, eight hits and three walks in 5 2-3 innings. He is 2-7 in his last 10 starts.
In the fourth, Davis walked and Jones followed with a drive to left to put Baltimore up 2-0. Ryan Flaherty hit a solo shot in the fifth, and Jones singled in the sixth and came home on a double-play grounder.
Toronto scored in the eighth on an RBI double by Rajai Davis. With runners on second and third and two outs, Darren O'Day came in to strike out Kelly Johnson.
NOTES: Toronto purchased the contracts of RHPs Shawn Hill and Bobby Korecky and transferred LHP J.A. Happ (foot) to the 60-day DL. ... Orioles LHP Randy Wolf is experiencing discomfort in his left elbow and will undergo an MRI on Tuesday. ... Seventeen of Jones' HRs have given the Orioles the lead. Baltimore is 23-8 when he homers. ... Toronto's first-game defeat was its sixth straight in Baltimore, its longest single-season skid in Charm City since 1980. The Orioles are 10-6 against the Blue Jays, clinching their first season series win over Toronto since 2004. ... Omar Vizquel got two hits to move into a tie with Mel Ott for 40th on the career list with 2,876.