HOUSTON -- Five times Juan Soto stepped into the batter's box during his debut with the New York Mets against the Houston Astros on Thursday. And five times baseball's $765 million man received steady boos from the Daikin Park crowd, none louder than in the ninth inning, with the game on the line.

Soto, fittingly, represented the game-winning run when he walked to the plate to face left-hander Josh Hader with runners on the corners and two outs. Hader, one of the best closers in the sport, quickly fell behind 3-0, then recovered with two strikes before unleashing a slider that darted away from Soto and out of the strike zone.

Soto waved and whiffed. He was, shockingly, fooled to end the Astros' 3-1 win.

"His best pitch is the fastball," Soto said, "so I was sitting on the fastball."

Thursday's Opening Day game, matching two clubs that expect to play in October, had a few pregame storylines. Future Hall of Famer Jose Altuve's first game as a left fielder in his age-35 season. Cam Smith, a 22-year-old slugger, making his major league debut less than a year after he was drafted. Clay Holmes, the former New York Yankees All-Star closer, starting his first game since 2018.

But it was, above all, about Soto.

A year ago, Soto also made his debut as the right fielder for a New York club in Houston to launch a pressure-packed season. But that team was the Yankees, the stadium was called Minute Maid Park and the pressure stemmed from the desire to impress with free agency waiting in November.

This time, he's a member of the Mets, an air conditioning company owns this ballpark's naming rights and the pressure stems from looking to prove he's worth the largest contract in professional sports history.

Batting second, Soto cracked a single in his first plate appearance as a Met against veteran left-hander Framber Valdez. He walked in the third inning, flied out in the sixth and walked again -- on four pitches -- in the eighth. It was a typical Soto showing, skillfully patient but willing and able to pounce on mistakes.

And yet the Mets did not score for eight innings. Valdez began his platform season by holding the Mets' potent lineup scoreless over seven innings on 90 pitches. New York showed signs of life against right-hander Bryan Abreu but still didn't manage to score. It wasn't until the ninth inning, when Hader clearly wasn't in peak form, that the Mets finally pushed a run across.

Starling Marte singled, Tyrone Taylor singled and Luisangel Acuna worked a 12-pitch walk to load the bases to begin the inning. After Hayden Senger struck out in his first career at-bat, Francisco Lindor delivered a sacrifice fly to pull the Mets within a run, bringing Soto to the plate.

"You feel it. I think everybody's like, man, let's get Juan up and see what happens," said Holmes, who surrendered three runs (two earned) over 4 innings in his Mets debut. "And we're able to do it. More times than not, we feel really good about it. And they made him work, and we were right there close. At the end of the day, if we got Juan up with a chance to win the game, anybody likes those chances."

What followed was a one-on-one battle between two players elite in their respective crafts. Soto said he saw Hader, a five-time All-Star, "really well" even though he presented a difficult lefty-lefty matchup with a three-quarters delivery.

"We all want to do something in a big spot," Soto said. "We all try to get the knock and try to bring the runs in and try to help the day in any way. But, for me, I don't mind taking a walk right there. I have Pete [Alonso] behind me, and he's a really good power hitter."

Soto would have walked if he had laid off the 3-2 slider. But he didn't, and his first signature Mets moment will have to wait at least another day.

Said Soto: "He just got me in that situation."