It might have been easier for Sixto Sánchez to say he felt nothing entering Sunday’s start against the Phillies at Marlins Park.

Just another team. Just another game.

But Sánchez could not wait to face the team that traded him to Miami in February 2019 as part of the J.T. Realmuto deal. The Phillies rediscovered why they once considered Sánchez their top pitching prospect and why so many people think he is a star in the making in a 2-1 loss in Game 1 of a seven-inning doubleheader. Sánchez allowed three hits and one run, walked three and struck out four in an impressive complete game.

• Box score

"I went out there with my positive mentality to win the game, and to show them a little more, [to ask], ‘Why did they trade me?’” Sánchez said through the team’s interpreter.

Sánchez struck out Andrew McCutchen swinging on a 99.1 mph fastball for the first out in the first inning. It was a sign of things to come. His four-seam fastball averaged 98.7 mph and hit 99.9 mph. He struck out Alec Bohm on a 100.4 mph fastball for the first out in the seventh. It was his hardest pitch of the afternoon.

Gerrit Cole is the only other starting pitcher in the past two seasons to record a 100 mph pitch in the seventh inning or later, according to Statcast. Cole did it twice, including once in the postseason. Sánchez is only the 11th starter in the pitch-tracking era (2008 to present) to record a 100 mph pitch in the seventh inning or later.

But Sánchez is more than just a thrower. He mixed his sinker (32 percent), four-seamer (22 percent), slider (21 percent), changeup (18 percent) and curveball (seven percent) well, keeping the Phillies off balance throughout the afternoon. Bohm hit a 98.7 mph fastball off the right-field wall for a double in the second inning. He advanced to third on a fielder’s choice and scored on Andrew Knapp’s sacrifice fly to center field to give the Phillies a 1-0 lead.

The Marlins scored twice with RBI singles against Philadelphia right-hander Ramón Rosso in the third to make it 2-1.

Sánchez and Rosso became friends coming up through the Phillies’ system. They were roommates at the Phillies’ camp in Clearwater, Fla., in 2018. The natives from the Dominican Republic still see each other in the offseason.

“I was very excited to share the mound with him,” Rosso said through the team’s interpreter. “We’re still good friends. … I think he’ll be a great pitcher. He has a lot of potential. If he keeps working hard he can definitely get there.”

“When he signed, I was one of the few Latino players he spoke with,” Sánchez said. “We have a good relationship. We'd hang out around the ballpark. Good guy. I think he's going to have a lot of success.”

Sánchez did not allow another hit until Jean Segura reached on an infield single with two outs in the sixth. The Phillies put runners on first and second with two outs in the seventh, but there was never a sense that Sánchez panicked or ran out of gas.

A complete game felt like a lock.

Sánchez’s debut against the organization that signed him to a $35,000 bonus in Feb. 2015 has been on the minds of Phillies fans since Miami promoted him on Aug. 22 -- not just because he is a remarkable talent, but because fans are concerned that Realmuto will sign with another team in the offseason.

• J.T. rests in Sunday's doubleheader

Realmuto will be a free agent, and he will be arguably the best position player available on the market. The Phillies have touched base with Realmuto’s agents, but there is no hint that a deal is close.

The idea that Realmuto signs elsewhere after only two seasons and Philadelphia has to face Sánchez for years as a constant reminder of what might have been is already making the most diehard Phillies fans queasy.

"I've got to tell you, I was more motivated to pitch against the Phillies,” Sánchez said. “I had my plan. I went out there with my head held high and got the victory. That makes me really happy.”