The final line was 10 walks, two hit batters and one painful error by third baseman Michael Young.
"You put that many guys on the bag, it's going to hurt you," manager Ron Washington said. "We've got to do better than that and we're capable of doing better than that."
Harden faced 19 batters over 3 2/3 innings, and only four players hit a ball fair off the 90 pitches he threw. Harden walked five, hit one, struck out eight and retired three batters on a foulout, popout and flyout.
He struck out five of the first seven hitters he faced before giving up his only hit -- a home run by Alex Gonzalez to lead off the third. Harden walked two batters in the fourth with the bases loaded to force in a pair of runs, although they were unearned because of the error by Young.
"It was just an odd night," Harden said. "I started off great, but everything was either a swing-and-miss, a foul ball or a ball. I couldn't get them to put anything in play. I threw a lot of pitches, and in the last inning, it caught up to me. I started getting the ball up."
The Rangers squeezed out an unearned run off Blue Jays starter Brian Tallet in the first and Gonzalez tied it with his home run in the third. It was still 1-1 going into the fourth, but Harden had already thrown 58 pitches through three innings and was starting to feel it.
"They made me throw a lot of pitches, and I lost my command in that last inning," Harden said. "Before I was keeping the ball down, but in that inning, I started getting the ball up."
Harden started the fourth by hitting Vernon Wells with a pitch and then walked Lyle Overbay. He struck out John Buck, but Edwin Encarnacion hit a potential inning-ending double-play grounder that Young couldn't come up with on the backhand. It went for an error that loaded the bases.
"It was tough on the defense," Harden said, trying to take the fall. "On Michael's play, he got a tough hop. It was cooler tonight, and when you're sitting there and the ball's not being put in play ... it's not what I want to do to the defense. It's tough to stay ready when you're not getting any action."
Young declined to let Harden take the blame for the error.
"That was my fault," Young said. "That's a play I should roll up right there. He's working hard, he's battling. In that situation, I want to make sure I pick him up."
Harden did get Gonzalez on a weak fly to left, holding Wells at third. But Harden proceeded to walk the next two hitters, forcing in two runs.
"He lost his rhythm," Washington said. "All of a sudden, he couldn't find the strike zone and everything was up."
Dustin Nippert bailed out Harden by getting Aaron Hill on a grounder to third, and the Rangers tied it up in the bottom of the fourth on back-to-back home runs by Vladimir Guerrero and Nelson Cruz.
Nippert couldn't keep it tied. He walked Adam Lind to lead off the fifth, and then Wells hit his second home run in two games to give the Blue Jays a 5-3 lead. The Blue Jays made it 6-3 in the seventh against Nippert and reliever Darren O'Day on two walks, a hit batter and a sacrifice fly. Wells added his second home run of the game off Darren Oliver in the ninth.
"We didn't have a lot of hits, but I guess we got them at the right time tonight," Blue Jays manager Cito Gaston said. "I guess you can call it 'Vernon Wells Night' tonight."
The Rangers' offense matched the Blue Jays with five hits. They just didn't get as many free passes. Tallet walked three -- two came across to score -- while relievers Kevin Gregg and Jason Frasor didn't walk any. Harden walked five and hit one, but his four relievers combined to equal that. Ultimately, the winning run was Nippert's walk to Lind in the fifth.
Not everything fell on Harden's shoulders.
"Walk 10, hit two," Washington said. "You're not going to win many games like that."