SAN DIEGO -- With Fernando Tatis Jr. slowly working his way back from a left wrist fracture and Manny Machado sidelined by a left ankle sprain, the Padres aren’t going to outslug many teams.

Their new formula goes something like this: (Strong starting pitching) plus (daily batting hero) minus (Machado) equals (just enough for victory).

Catcher Jorge Alfaro has shown a knack for being the middle part of that formula. He delivered an RBI single in the 11th inning Tuesday night for a 3-2 walk-off victory over the D-backs at Petco Park. It was the Padres’ sixth walk-off victory of 2022 -- tops among National League teams and only behind the Yankees overall -- and Alfaro has had the honors twice.

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“It’s good to see his approach kind of morphing into something we can work with right now,” acting manager Ryan Christenson said. “During his career, he’s had trouble controlling the zone and maybe offering outside the zone. But he’s tightened that zone up a lot this year, and I think that’s what added to his success and him having some big hits for us.”

Alfaro pulled a 2-1 fastball from Ian Kennedy through the shortstop hole with one out to drive in automatic runner José Azocar from second base. During the at-bat, he gave himself a mental reminder to stick with the approach Christenson mentioned.

“My first swing, I tried to cut the ball in half,” Alfaro said. “I stepped out: ‘You have to relax. You just have to hit the ball, try to put the ball in play.’”

Alfaro’s knock left the Padres with a 2-0 record since Machado’s ankle injury and still in a virtual tie with the powerhouse Dodgers for first place in the NL West. (Los Angeles is percentage points ahead of San Diego.) The Padres improved to 8-3 in extra-inning games, and they lead MLB in extra-inning games played and won.

Left-hander Sean Manaea provided the strong starting pitching, delivering the Padres’ 39th quality start of 2022 -- tops in the Majors -- by holding Arizona to two runs on four hits and three walks over six innings while notching six strikeouts. The two runs came on a third-inning inside-the-park home run by Jordan Luplow after Trent Grisham failed to make a diving catch in center field and saw the ball bounce over him and toward the warning track.

Eric Hosmer spent April as Machado’s co-star in carrying the offense, but has faded since. He stepped back into the spotlight in the sixth inning, sending a full-count curveball from D-backs starter Zac Gallen into one of the deepest parts of Petco Park for a game-tying solo home run.

Hosmer’s 401-foot drive just cleared the wall in right-center field. In fact, he had to survive a replay review when a fan reached for the ball above the wall before it deflected onto the warning track. Once the call on the field was confirmed, Hosmer was credited with his fifth homer of the season and his first since May 11 at home against the Cubs.

Hosmer had gone 138 plate appearances and 127 at-bats without a homer before connecting on the 17th pitch -- the seventh curveball -- he saw from Gallen. Hosmer struck out each of his first two at-bats vs. Gallen, who registered a career-high 11 K’s.

“That was a step in the right direction, seeing that ball leave the yard,” Christenson said.

As Hosmer tries to redirect his season to the right direction, Alfaro continues to enjoy sustained success in his first season in San Diego. His OPS is .803 –-- second only to Machado on the Padres. Alfaro’s walk-off Tuesday wasn’t as dramatic as his first of 2022 -- a home run on Mother’s Day against his former club, the Marlins -- but it brought the same result: a win.

“He brings it,” Manaea said. “He’s got the energy; he’s got the flair.”

The energy has never been the issue. Alfaro is learning to rein in that energy when calmness is in order -- make the pitcher do the work, don’t expand the zone in big spots and help the pitcher.

“I know whenever the pitch is close to me, I know I can get to it,” Alfaro said. “I’m trying to focus on my hot spot -- just compete and battle.”