PORT ST. LUCIE – If this were Opening Day, the Mets would have wanted their $137.5 million back.
After all, three runs on four hits (including a long homer to left) in two innings isn’t what they have in mind from Johan Santana.
But as hotly anticipated as his debut as a Met was, it was also the prize left-hander’s first game in five months. That important fact made his ugly line against the Cardinals yesterday completely beside the point to Santana and the Amazin’s.
“This is just the beginning,” Santana said after throwing 30 pitches in the Mets’ 5-4 loss at Tradition Field. “The numbers might say something different, but I felt good.”
The Mets agreed, showing no sign of concern after the two-time Cy Young winner gave up hard hits to three of the first five batters he faced. Even the first-pitch blast over the wall by one-time AL MVP Juan Gonzalez that put Santana in a quick 3-0 hole elicited yawns.
“A very positive day,” Mets pitching coach Rick Peterson said. “Johan threw the ball outstanding.”
Santana also allowed a two-out triple in the gap to No. 9 hitter Brendan Ryan in the second, but the Cardinals were just as adamant that nothing should be read into yesterday’s success against the Mets’ Venezuelan ace.
“He’s still Johan – good fastball, good change-up and good control,” said third baseman Troy Glaus, who reached on a fielder’s choice. “It’s spring training. We were just looking for a good pitch to hit and do something with it. I still don’t like facing him.”
Gonzalez, the ex-Rangers slugger trying to revive his career with the Cardinals this spring, shrugged at mention of his shot off Santana.
“He’s still going to be great,” Gonzalez said. “I just got a good fastball to hit. He’s still got the best change-up of any left-hander in the game.”
But as much as everyone tried to downplay it, the vibe and atmosphere made this feel like anything but a February game in the Grapefruit League.
Santana’s debut was broadcast live on TV in New York, as a crowd of more than 5,000 (including Bobby Knight) filled the stands. The entire Mets bench also thronged to the top step of the dugout to watch his every pitch in the first.
It was a far cry from anything Santana experienced as a Twin, which explained the obvious look of relief on his face afterward.
“I’m definitely glad it’s over,” said Santana, who struck out one and walked none. “There were a lot of people waiting for this, and now it’s finally done.”
What those people and the Mets saw – despite the final numbers – was a crisp and at times impressive performance from Santana. A tidy 22 of his 30 pitches were strikes. Santana was so efficient he needed to throw 15 more pitches in the bullpen afterward to reach his scheduled 45-pitch workload.
As well as facing an unfamiliar NL lineup, Santana had trouble in the first because he threw almost strictly fastballs in a bid to work his velocity back up to its normal 95-mph range.
That zip isn’t there yet (Santana’s highest radar reading yesterday was 91 mph), and the free-swinging Cardinals took advantage.
“I was trying to throw my fastball and locate all my pitches, but those guys were aggressive, swinging right away and putting the ball in play,” said Santana, who also was touched for a double by Albert Pujols in the first.
Working with backup catcher Ramon Castro instead of starter Brian Schneider, Santana adjusted to the Cardinals’ hack attack in the second with a mix of sliders and his trademark change-up.
That went a lot smoother, leading to a scoreless inning and post-game vow from Santana.
“I’ll be ready,” he said. “This is just the start of my career here. We’ll see where we are at the end.”
bhubbuch@nypost.com