DETROIT -- With several injuries in the outfield, the Giants tried out a new defensive alignment on Friday night. They shifted middle infielder Thairo Estrada to left field and moved third baseman David Villar to second to maximize the amount of right-handed bats in their lineup against Tigers left-hander Joey Wentz.

But Villar’s inexperience at second showed when he committed a costly mental mistake that helped open the door for the Tigers to walk it off, 7-5, in 11 innings at Comerica Park.

The Giants clawed back from down 4-1 to tie the game on J.D. Davis’ three-run blast in the eighth inning and briefly seized a 5-4 lead on LaMonte Wade Jr.’s RBI single in the top of the 11th. San Francisco came within one out of taking the first game of its six-game road trip, but flamethrower Camilo Doval -- who worked multiple innings for the first time this year -- couldn’t close it out, surrendering a game-winning, three-run homer to Nick Maton.

Poor decision-making by Villar, who was making only his ninth career start at second in the Majors, helped prolong the Tigers’ final rally. With the automatic runner at second to start the bottom of the 11th, Villar fielded a chopper off the bat of Zach McKinstry and tried to get the lead runner at third, but his throw arrived late, preventing J.D. Davis from recording an out at third.

Doval came back to strike out Jake Rogers and Matt Vierling, but he misplaced a 3-0 sinker to Maton, who drove it out to right field to hand the Giants their first extra-innings loss of the year.

Villar accepted full responsibility for the mistake and said manager Gabe Kapler and shortstop Brandon Crawford both spoke to him about the play afterward.

“My initial thought was if I can get this ball moving towards third, maybe get the out at third,” Villar said. “I didn’t take into consideration, with Doval on the mound, you’ve got a guy up there with some plus stuff. He can get the strikeouts. Unfortunately, I’m going to have to try to sleep on this one tonight. It’s a learning experience. It sucks. The loss falls on me right there. It’s something I’ve got to face, but hopefully, I can move forward from this.”

“It’s not a play that we really practice,” Kapler said. “You see that play made very rarely, so unless you’re absolutely certain you have an out at third base, just throw the ball to first base. He understands that.”

With Mitch Haniger and Austin Slater on the injured list and Michael Conforto dealing with left calf tightness, the Giants were forced to play Estrada and Villar out of their natural positions, but Villar said he didn’t want to make any excuses for his miscue.

“That’s the mental part of the game,” Villar said. “You’ve got to stay locked in the whole time. It’s a decision that I made pre-pitch, and I’ve got to live with it. But I’m not going to sit here and make any excuses. I’ve had plenty of games here at the Major League level at second base, and it’s a play that I normally make to first base 99 out of 100 times. But something different just happened tonight, and I’ve got to move on from it.”

The stinging defeat overshadowed a huge game from Estrada, who finished 3-for-3 and fell a triple shy of the cycle, boosting his batting average to a team-high .370 over 12 games this year.

The 27-year-old gave the Giants an early lead by blasting Wentz’s eighth pitch of the game 441 feet out to left-center field for his third homer of the season. That proved to be the only damage allowed by Wentz, who struck out seven over 5 2/3 innings of one-run ball for the Tigers.

The Giants trailed, 4-1, entering the eighth inning, but Estrada sparked a rally by drawing a leadoff walk against reliever Garrett Hill. Mike Yastrzemski followed with a one-out single to put a pair of runners on for Davis, who whacked a first-pitch fastball from Mason Englert out to right field for a game-tying, three run homer.

“It seemed like the sixth or seventh inning, we got our second wind and got some energy,” Davis said. “We started to string some things together and started to put more pressure. I just ambushed the first pitch that I saw. … To tie the game, get back into it and take the lead, it was definitely a tough pill to swallow. But no excuses. We’ve got to get up and play tomorrow.”