Lowe had only one loss since May 17, and was 5-0 with a 1.06 ERA in his last five starts against the Orioles.
The right-hander maintained his mastery over Baltimore for five innings, but was roughed up in a seven-run sixth that lifted the Orioles to an 11-2 victory Saturday night.
Baltimore trailed 2-1 before sending 10 batters to the plate in the sixth.
“Obviously, you don’t expect something like that against someone like Lowe, especially the way he’s pitched against us the past couple years,” said Jeff Conine, who started the uprising with a single.
Jay Gibbons went 4-for-4 with three doubles and Rodrigo Lopez (4-6) allowed two runs in six innings to help the Orioles win their eighth straight home game and improve to 11-5 since the All-Star break.
On Sunday, the Orioles will try to complete their first three-game sweep of the Red Sox in Baltimore since September 1974.
Nomar Garciaparra homered for the Red Sox, whose four-game losing streak is one short of their season high. Boston, which fell 4 1/2 games behind the first-place New York Yankees in the AL East, has been outscored 29-8 during the current skid.
“Give it to them, they just swung the bats today and they beat us. That’s really all there is to it,” Garciaparra said.
Lowe (11-5) gave up six runs, five earned, and eight hits over 5 2-3 innings in falling to 8-2 over his last 15 starts.
Held to an unearned run through the first five innings, the Orioles pulled away in the sixth. Conine hit a leadoff single, went to third on a single by Gibbons and scored when Tony Batista rolled an opposite-field single to right.
“This game’s amazing,” Orioles manager Mike Hargrove said. “You’re sitting there hoping Fordyce hits a sacrifice fly so you can take a one-run lead, and the next thing you know you’re up by six. It’s a crazy game.”
Jose Morban followed with a two-run single up the middle to chase Lowe, who had allowed only five earned runs in his previous 12 appearances at Camden Yards.
“He was cruising along and then they got those three straight hits off him on those groundballs. Then it fell apart,” Boston manager Grady Little said. “It was a good game to that point.”
That left the Red Sox wondering what must be done for them to get back on course.
“Everyone’s got to contribute, but the key is for each one not to be trying to be the one,” Little said. “They have to do it collectively and not try to do too much at this point.”
The game attracted 49,334 fans, the third sellout of the season at Camden Yards and the second-largest crowd in the 12-year history of the ballpark.
The Orioles took a 1-0 lead with an unearned run in the first. Conine hit a two-out single and scored when Boston catcher Jason Varitek dropped the relay from Garciaparra on Gibbons’ double.
After stranding a runner in scoring position in the first and second innings, Boston finally broke through in the fifth. Johnny Damon singled ahead of Garciaparra, who hit a 1-0 fastball into the left-field seats for his 18th homer.
With Lowe on the mound, the drive loomed large.
“Your heart sinks, because you know Lowe doesn’t give up a lot of runs,”Hargrove said. “But he did tonight.”
Orioles LF Melvin Mora missed his fifth straight start with a hand injury. … Boston 3B Bill Mueller was not in the starting lineup after having a wisdom tooth extracted Friday. … Gibbons’ three doubles gave him a career-high 31 this season … Morban had one RBI this season before histwo-run single.