BOSTON(AP) The Boston Red Sox and their bullpen are stumbling toward the All-Star break.

David DeJesus hit a go-ahead two-run homer in the sixth inning as the Kansas City Royals rallied from an early four-run deficit and knocked the Red Sox out of sole possession of first place in the A.L. East with an 8-6 victory Thursday night.

Boston is 5-5 in its last 10 games and the bullpen has absorbed four of those losses.

David Ortiz hit his 300th career homer for Boston, which fell to 3-4 on its 10-game homestand after splitting six games against Seattle and Oakland. The loss, coupled with the New York Yankees ' 6-4 victory over Minnesota, has the teams tied with three games remaining before the All-Star break.

''Those guys just bounced back tonight and scored runs at the right time,'' Ortiz said. ''The Yankees are not a surprise. They are playing great.''

Luke Hochevar (5-3) won for the fifth time in seven starts, despite allowing nine hits and five runs in six innings. Joakim Soria recorded four outs for his 14th save.

''Late in the games, you can feel that Red Sox aura here,'' DeJesus said. ''But once we got Soria in the game, we feel confident he can do the job, and he did the job as usual.''

Mark Teahen and Willie Bloomquist each had three hits, and Alberto Callaspo had a pair of RBI doubles to help Kansas City avoid its third consecutive loss. The Royals also beat Boston for the sixth time in its last 23 tries at Fenway Park.

''We had some grinding at-bats,'' Royals manager Trey Hillman said. ''Guys saw a lot of pitches and continued to battle.''

Boston's bullpen combined to allow five runs in four innings after starter Brad Penny was staked to a 5-3 lead after five innings. He allowed three runs and six hits, and has only one win in his last six starts.

''There are times when things dont always work out,'' Justin Masterson said. ''Lately, it has been a different guy missing on a different pitch at a different time.''

Trailing 5-3 in the sixth, the Royals scored four times to take the lead. Teahen led off with a double and after Manny Delcarmen retired the next two batters, Callaspo knocked in Teahen with his second double of the game to make it 5-4.

Masterson (3-3) relieved Delcarmen and Ryan Freel tied it after working the count full and singling in Callaspo. DeJesus capped off the inning with a two-run shot into the Royals' bullpen for a 7-5 lead.

''Our bullpen gave up some runs and when you look for four innings of relief that can happen,'' Red Sox manager Terry Francona said. ''Masterson made a real good pitch on Freel that falls and that to me is the big pitch.''

Willie Bloomquist added an insurance run for Kansas City with an RBI triple in the eighth off former Royals reliever Ramon Ramirez .

Boston threatened in the eighth when it loaded the bases off Juan Cruz on a pair of walks to David Ortiz and Jason Bay and a fielder's choice, but got just one run on Mark Kotsay 's sacrifice fly. Soria relieved Cruz and struck out Nick Green to end the threat. Cruz had retired 18 straight batters before walking Ortiz.

The Royals scored three times in the fourth on four hits, two stolen bases and a throwing error by catcher Jason Varitek .

''They definitely picked me up. That was huge,'' Hochevar said. ''We've been swinging the bats well, but when you put up a 3-spot, that's big.''

Boston's Dustin Pedroia made it 5-3 when he hit his fourth home run in the fifth. He also keyed a three-run first when he doubled off Hochevar before being singled home by Kevin Youkilis . Ortiz followed with a two-run shot - his 10th in the last 29 games - to give the Red Sox a 3-0 lead.

NOTES: Ortiz became the 19th active player to reach 300 home runs, and first for Boston since Manny Ramirez did it in 2002. This was the first game between the clubs since Boston traded outfielder Coco Crisp to the Royals in exchange for Ramirez in November. Crisp is out for the season following shoulder surgery, while Ramirez has a 2.19 ERA in 37 appearances for the Red Sox . Mike Jacobs was the only Royals starter without a hit.