PHOENIX -- It was the ninth inning of a scoreless game on Tuesday night and Reds starting pitcher Tyler Mahle gave up an infield hit and was well over 100 pitches against the D-backs. Mahle looked into the dugout and met the eyes of manager David Bell.

"I peeked in there because I knew the pitch count was up," Mahle explained. "I said, 'I want to stay in.'"

"I wanted to make sure he was OK," Bell said. "He looked over and gave me a little nod. I’ll probably remember that look for the rest of my career. It was pretty cool to be a part of that.”

Mahle pitched a career-high nine scoreless innings -- two more than his previous high -- but didn't get credit for a complete game, a shutout or even the win. But he was a huge part of the Reds getting a 5-3 victory over Arizona in 12 innings at Chase Field.

"When guys have performances like that, you want them to be rewarded," Bell said. "Several times [in extras], we thought we had it won. They thought they had it won. To come out on top is definitely a good feeling.”

While giving up three hits and throwing 119 pitches (83 strikes), Mahle tied a career high with 12 strikeouts, which he'd done twice previously.

"That was the art of pitching. He was unbelievable tonight, just complete domination," catcher Aramis Garcia said.

Entering as the Major League leader this season for working into 62 full counts and tied for fourth in walks with 30, Mahle didn't reach three balls until facing Josh Rojas, who ran a full count with two outs in the sixth inning. Daulton Varsho also worked a full count in the ninth, but Mahle did not walk any batters in the game.

"It’s a perfect example -- if you get ahead of guys, good things will happen," Mahle said.

Like in his previous start, a big key to Mahle's success was his fastball -- which he threw 69 times (58 percent). Mahle recorded 11 whiffs against 39 swings and 14 called strikes. Eleven of the 12 strikeouts Mahle recorded came via his fastball -- often at the top of the strike zone.

"It’s been a great pitch for me, especially the last couple games," Mahle added. "We have a lot of confidence in that."

Mahle shared all of the credit for his performance with Garcia -- the backup moved into a starting role after Tyler Stephenson went on the 10-day IL last week with a fractured right thumb.

On a couple of occasions, Mahle told Garcia he must have been reading his mind about pitch selection.

"I know you’ve got to make pitches, but the sequences he was calling was the greatest I’ve ever seen, by far," Mahle said. "It was the greatest game I think I’ve ever seen called. Keeping them off-balanced, going in, out, up, down -- that was really cool. I had to shake a couple times, but I shook to the wrong pitch. He was probably right. That was really cool. I’m really proud of him."

Garcia considered that the best compliment he could receive.

"That really means a lot to me," Garcia said. "I spend a lot of time getting to know these guys, a lot of time watching video and doing my homework and my due diligence."

As good as Mahle has been, he's lacked good fortune. In his last four starts, the right-hander is 0-0 with a 1.30 ERA. In all four games, he was the victim of a blown save.

"I’m more focused on going out there and giving us a chance to win," Mahle said. "Whatever happens, happens. … That’s what good starters do."

All of the scoring happened in extra innings as the Reds took a one-run lead in the 10th and a two-run lead in the 11th and blew both of them. Albert Almora Jr.'s RBI triple in the 12th, followed by Jonathan India's RBI single put them on top for good, giving Cincinnati its third straight win with a chance to sweep the series Wednesday.

“What a game. I can’t even remember what happened," Bell said. "All I know is both teams continue to play and battle and do everything in their power to win the game. Fortunately, we came out on top. Games like that can go either way. I’m really happy for our team to be able to grind it out there."