PHOENIX -- A day that began with the focus on starter Adam Wainwright returning to the mound in quest of career win No. 199 ultimately zeroed in on the late-game theatrics of the Cardinals’ offense, which rallied in the ninth to score five runs, as St. Louis claimed the opening contest of the series in Arizona, 10-6.

The crucial blow was delivered by Tyler O'Neill, who arrived at Chase Field on Monday scheduled for an off-day after four consecutive starts. Thrust into action as a defensive replacement in the seventh, it was his bases-clearing double in the ninth that provided a cushion for the bottom frame.

It was also -- with one swing on a hanging slider -- a breath of fresh air in a season that has been sidetracked by a lower back strain that forced O'Neill to miss two and a half months of game action.

“I feel like I'm in a really good spot physically,” O’Neill said after playing in just his fifth game since returning from the IL. “I formulated a really solid routine that gets me going every day. 

“Had a handful of at-bats down at Triple-A to get me ready, whatever it took to get me to the spot where I am now. To me, it’s just getting those everyday reps and continuing to get that timing down, continuing to be in a good spot.”

“It's really nice to have him offensively, [a player] who, 30-plus homers and driving [in] runs and being a real threat at the plate,” manager Oliver Marmol said. “He's confident, he's feeling good and he's bought into what needs to happen in order to get back to that. I think we'll see that Tyler O’Neill again.”

The last time O’Neill stepped foot on the diamond in Arizona came back in March during the World Baseball Classic with Team Canada. Looking to put a 1-for-11 performance with the national team in 2017 in the rearview mirror, the 28-year-old outfielder was a vital cog at the heart of the order, going 8-for-13 over four games with an eye-popping .722 on-base percentage.

But for all of the promise that the year began with, O’Neill hit a cold spell early on that, coupled with the Cardinals’ considerable outfield depth, led to a decrease in playing time. And then injury struck, forcing the slugger to the sidelines.

O’Neill's return to full health coincides with Lars Nootbaar’s, which means St. Louis once again finds itself with four capable outfielders -- including Dylan Carlson and Jordan Walker -- for three everyday slots. Given the aforementioned 34-homer campaign on O'Neill's ledger in 2021, there’s reason to believe that teams in the thick of the pennant chase looking to add right-handed thump could be interested in his services.

“I mean, obviously there's lots going on; we’ll see what the front office wants to do over the next week here,” O’Neill said. “But, you know, as a player, it's not something that I want to think about. Every day, it's trying to show up to the ballpark, show up with a good attitude, show up and compete with these guys, and you know, that puts us in a good spot at the end of the day.”

Originally, Wainwright was supposed to merely throw a live batting practice session Monday in front of Cardinals staff. But when it became apparent that the club would need innings in game action, the 41-year-old toed the rubber in front of 23,184 in attendance and largely kept a D-backs lineup that entered the night ranked fourth in the National League in OPS (.756) under wraps, scattering four singles and two walks across five frames.

Taking the hill with a soft 65-pitch target, Wainwright relied on his bread and butter. His combined sinker and curveball usage rated as his second-highest this season, with 71.1 percent (54 of 76) of his pitches coming on those two offerings.

“Stuff was way better, a lot more life,” Wainwright said. “Breaking ball was snapping, sinker was sinking. Now we just want to hone it a little bit more, but that’s certainly a game that I can build off of. I’m very excited about moving forward from here.”

Wainwright, who insisted that the cortisone shot he received had done the trick and returned him to feeling like himself, tinkered with new arm slots to further add to his expansive repertoire.

“I’ve always wanted to do that," Wainwright said. "I just never really knew if I should. You know, why not right now? Don’t leave anything in the tank.”