PHOENIX -- Entering Wednesday night's game against the Dodgers, Sergio Alcántara had hit just four home runs during his two stints with the D-backs this year, but he certainly made them count -- all four either tied the game or gave the D-backs a lead.

Alcántara added another homer to his total Wednesday, this one a three-run shot as the D-backs walked off the Dodgers, 5-3, in 10 innings.

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It's been a topsy-turvy year for Alcántara. He went to Spring Training with the Cubs before being traded to the D-backs for cash. Out of Minor League options, he opened the season with the D-backs before they designated him for assignment and the Padres claimed him on waivers on May 9.

The Padres then designated him for assignment in early July and the D-backs snagged him back off waivers on July 5.

"It was a little difficult," Alcántara said via interpreter Alex Arpiza. "I've never gone through so many transactions -- being released, then signed and released again. So it's just about preparation, working hard for whatever the team needs me."

The D-backs needed him Wednesday after eventful ninth and 10th innings.

It started in the bottom of the ninth when D-backs rookie outfielder Jake McCarthy singled to left off reliever Evan Phillips to open the inning.

The speedy McCarthy easily stole second base and he moved to third on Ketel Marte's groundout.

During their advance work on the Dodgers, the D-backs noticed that catcher Austin Barnes had a tendency to lob the ball back to the pitcher between pitches. When McCarthy got to third with two outs and Corbin Carroll at the plate, he was given the freedom to try and steal home if he thought he could.

On the first pitch to Carroll, McCarthy saw Barnes give a cursory check of him at third before lobbing the ball back to Phillips. That was when he made his decision.

"Just on my own, I thought, 'Hey, if he does that again I can probably make a play here,'" McCarthy said.

On the next pitch, Carroll foul-tipped the ball back into Barnes' glove for a strike. Barnes lobbed the ball back to Phillips and McCarthy was off.

Fortunately for the Dodgers, Phillips caught the ball and quickly got a strike to Barnes to barely get McCarthy at the plate.

D-backs manager Torey Lovullo challenged the call on two fronts -- that McCarthy was safe and/or that Barnes had blocked the plate.

"I asked to [review] the whole thing," Lovullo said. "I wanted the full-meal deal."

The call was confirmed and the game went to extra innings.

While Lovullo had greenlighted a steal attempt of that kind, he said he would have liked it had McCarthy gotten another few steps closer to the plate before attempting it.

"I just wish in hindsight, I had got a more aggressive lead to start," McCarthy said. "Because when [Barnes] made eye contact with me, I took a step back, but I was planning on going home so I just wish it was a more extended lead. Maybe I could have gotten there."

Instead it was Alcántara who came through again for the D-backs when they needed it.