Mauro Gomez hit a tiebreaking, two-run triple in the ninth inning and Nava made a game-saving grab in the outfield and Boston beat Toronto 8-5 on Friday night, snapping a six-game losing streak against the Blue Jays.
Boston had lost six of seven overall coming in, but bounced back after falling behind 3-0 and later blowing a 5-3 lead.
Ryan Lavarnway hit a three-run homer and finished with four RBIs but no one was more important than Nava, who hit a two-run single in the fifth, then left his feet to haul in a sinking line drive from Adam Lind in the eighth, keeping the go-ahead run rooted at second base.
"That was awesome," Lavarnway said of Nava's backhanded catch. "That's one of the most spectacular catches I've seen all year, especially in a tie game. I'd say that was a game-saving catch."
Nava said instinct took over as he raced into the gap to track down the ball.
"That one felt good, especially with what was on the line at the time," he said. "It meant a lot for the team."
Red Sox manager Bobby Valentine called Nava's grab "spectacular."
"Once it started slicing, I thought maybe he could intercept it," Valentine said. "I didn't know it would take a dive."
Darren Oliver (3-3) lost for the first time since May 23 at Tampa Bay, giving up one run and two hits in one-plus inning.
Jacoby Ellsbury singled off Oliver to begin the ninth, bringing Casey Janssen out of the bullpen. Mike Aviles flied out and Cody Ross singled before Gomez tripled to the wall in right-center. Lavarnway followed with a sacrifice fly.
"Mauro is a pretty good hitter," Valentine said. "He's been playing a lot against left-handers, but I left him in against a right-hander there and he didn't try to do too much. He took a slider into right-center field that I thought was caught for a second. It's a game of inches: Daniel makes the catch, Gose doesn't."
The Blue Jays took the lead by scoring three times off Daisuke Matsuzaka in the third, all without a hit. Moises Sierra was hit by a pitch and Anthony Gose and Colby Rasmus walked to load the bases. Sierra and Gose both scored on wild pitches before Rasmus came home on Lind's groundout.
"It was a real waste that I gave up a few runs without giving up any hits," Matsuzaka said through a translator. "It was really unfortunate that I wasn't able to make a small adjustment during that inning and get out of it quicker."
Boston tied it in the fourth on Lavarnway's homer, his second, and took a 5-3 lead on Nava's two-run single off Chad Jenkins in the fifth, snapping a stretch of 19 scoreless innings by Blue Jays relievers.
Aviles, who scored on Nava's hit, had escaped two batters earlier by evading a tag attempt from third baseman Brett Lawrie. Aviles was at second when Gomez grounded to third. Lawrie tried to tag Aviles, but he spun around, then scampered to the bag ahead of Lawrie as Gomez also reached safely.
"How about that move?," Valentine asked. "I don't think he was out of the baseline. Mike didn't give up, he gave everything he had to avoid the tag and he did."
Both Lawrie and Blue Jays manager John Farrell argued with umpire Todd Tichenor, saying Aviles had gone out of the baseline.
"To me, it looked like he went outside the established base line but the call stood as it was," Farrell said.
Lavarnway walked before Nava lined his tiebreaking single.
Junichi Tazawa worked a scoreless seventh but Vicente Padilla couldn't preserve the win for Matsuzaka, surrendering a leadoff single to Rasmus in the eighth and giving up a game-tying double to Lawrie. Nava followed with a diving catch on Lind's liner to left, keeping Lawrie at second base, before Carpenter came on to finish the inning.
Toronto's Aaron Laffey gave up three runs and four hits in 3 2/3 innings, his shortest start of the season, and remains winless in five starts.
Jason Frasor pitched the sixth and seventh for Toronto, the 500th appearance of his Blue Jays career.
Toronto slugger Edwin Encarnacion was held out of the lineup with a sore left wrist. He was hit by a pitch from Seattle ace Felix Hernandez in Thursday's win over the Mariners. He is expected to play Saturday. ... Blue Jays pitching coach Bruce Walton, who had to leave the bench after being struck by Edwin Encarnacion's broken bat in the first inning Thursday, was back in the dugout Friday. Walton sustained bruises but avoided cuts and broken bones after he was hit by the barrel of Encarnacion's broken maple bat. ... Red Sox 2B Dustin Pedroia missed his second straight game following the birth of his second son and is expected to rejoin the team Saturday, Valentine said. ... Boston RHP John Lackey (elbow surgery) felt good after a 25-pitch bullpen session and will likely throw another next week, Valentine said. Lackey is aiming for a two-inning stint in an instructional league game before season's end.