Boston loses 3-2 to Baltimore
Instead, David Ortiz continued to search for answers to his slump.
Ortiz struck out with a runner on third in the eighth inning, and the Red Sox went on to a 3-2 loss. The All-Star slugger went 0 for 4 and is hitless in his last 22 at-bats.
''It's not the end of the world,'' he said. ''You know what I'm saying? Papi can struggle, too. I'll be back.''
The Red Sox were 1 for 10 with runners in scoring position and left five men on base.
Manager John Farrell said he was confident Ortiz would snap out of his slump soon enough.
''He's just going through a spell right now where he's working to get out of it,'' Farrell said. ''He's proving that he's human.''
The AL East-leading Red Sox remained 2 1/2 games ahead of Tampa Bay in the AL East, with Baltimore another four games back.
Chris Tillman pitched seven strong innings to earn his 15th win of the season, helping the Orioles avert a three-game series sweep. Manny Machado had two hits, including a two-run double that gave them the lead for good in the third inning.
Tillman (15-4), who had never won more than nine games in a season before this year, allowed two runs and six hits while striking out eight. Only Detroit's Max Scherzer, who has won 19 games, has more major league victories this season.
Jim Johnson pitched the ninth for his AL-leading 41st save.
Nava doubled and scored on Stephen Drew's single to give Boston a 1-0 lead in the second inning. But the Orioles took the lead on Machado's double, and then made it 3-1 in the fifth when Lester walked Adam Jones with two outs and Chris Davis doubled off the Green Monster.
NOTES: Victorino's seven homers in August tie his career single-month high, set in July 2008. It's the most homers by a Sox right fielder in a month since J.D. Drew's 12 in June 2008. ... Boston 1B Mike Carp, who had the game-winning hit on Wednesday night, was scratched with a sore left shoulder. ... The Orioles, who closed to 6 1/2 games behind Boston, still have six games left against the Red Sox in September, including the last three games of the season in Baltimore. ... Baltimore OF Nate McLouth was hit in the hand while offering at a pitch in the third inning. He remained in the game and eventually reached on a walk. ... Boston CF Jacoby Ellsbury singled and stole his 50th base of the season in the eighth inning. It's the third 50 stolen base season of his career.