PHILADELPHIA -- Phillies president of baseball operations Dave Dombrowski said one of the reasons the club felt comfortable signing Cristopher Sánchez to an extension at this point is that he's not the type of player to rest on laurels.

It's only one game, but so far so good.

Less than 24 hours after signing his new contract, Sánchez showed exactly why the Phils were so eager to keep him around for the foreseeable future. The left-hander breezed through seven scoreless innings in classic Sánchez fashion in a 4-1 win over the D-backs in the rubber game on Sunday afternoon at Citizens Bank Park.

"It's incredible signing the extension yesterday and then having this outing today," Sánchez said via team interpreter Diego D'Aniello. "But we have to keep going, we have to keep doing things right."

Sánchez struck out four and allowed just three hits and zero walks. He needed only 80 pitches to navigate his seven frames while facing only one over the minimum.

And the fact he did it all after signing a life-changing contract and fielding countless congratulations from friends and family -- “It was like a holiday for them,” he said -- only speaks to his maturation.

“He’s grown up, man,” manager Rob Thomson said. “He was brilliant today. He just did a masterful job.”

Sánchez lowered his season ERA to 2.67 with this latest gem. An even more incredible number is that he's allowed only one home run in 15 starts.

Sánchez is the first pitcher to allow one homer or fewer through his first 15 starts of a season since Jake Peavy in 2007 -- and he's the first Phillies pitcher to do so over any 15-start span within a season since Jerry Koosman in 1984.

"I told him I needed to have a sit-down talk with him about how to not give up homers," joked teammate Aaron Nola.

But it's a lot more than limiting home runs. Sánchez has walked only 24 batters. He's struck out 70.

All of it together makes him just the fifth pitcher in AL/NL history -- and only the second in the past 100 years -- with a sub-3.00 ERA, 70 strikeouts, 25 or fewer walks and no more than one home run allowed through the first 15 starts of a season. The others are: Bill Gullickson (1981) and Hall of Famers Walter Johnson (1916, '14), Grover Alexander (1915) and Charles Bender (1912).

"He's worked extremely hard to make himself better; make himself a really good big league pitcher," Phillies ace Zack Wheeler said. "I'm happy to have him here for a long time now. I think it was a smart move by the front office."

Sánchez entered Sunday with the third-highest ground-ball rate in the Majors at 60.4%. It's no surprise then that he induced a pair of double plays to wipe out two of the three baserunners he permitted.

It's also no surprise that both double plays came on his changeup.

Sánchez's changeup is arguably the most dominant single pitch on Philadelphia’s staff. Opponents entered Sunday hitting just .166 (49-for-295) with a .258 slugging percentage against the offering through his career. The D-backs went just 1-for-10 against the changeup with three strikeouts in addition to those two double plays.

Now, toss in Sánchez's increased fastball velocity this season. Entering Sunday, his sinker was averaging 94.5 mph -- up from 92.1 mph last year. The Phillies always knew he had that type of velocity, but he couldn't harness it with any sort of control -- until now.

"He's a guy who threw really hard before he got up here, but his command wasn't the best," Nola said. "So the velocity kind of dipped down while he got his command better, but now that velocity is creeping up again and he was able to keep that command, so it's been impressive.

"And obviously, he's got that changeup, which really makes him elite."

Sánchez's stellar outing helped secure a series victory over a D-backs team that ended the Phillies' season in shocking fashion in last year's NL Championship Series. Sánchez had a short leash in his Game 4 start against Arizona, throwing just 38 pitches over 2 1/3 innings in his lone appearance in the 2023 postseason.

Now under contract through 2028 with club options for '29 and '30, Sánchez figures to have a much bigger impact in future potential postseason outings -- both in '24 and beyond.

“As a whole, we have one goal and that is to win the World Series this year,” he said. “I want to be a part of that and help the team as much as I can during that run.”