Jose Reyes started to look like the Reyes of old in the ninth.
And when Rod Barajas sent a screamer to left field, it seemed that the Mets shortstop was about to score the tying run — with David Wright to follow with the winning run — in his first game in nearly a year.
But Willie Harris, who has robbed the Mets before, dove and made a terrific play to end the threat — and the game — in the Mets’ 4-3 loss to the Nationals yesterday at Citi Field.
“I was jumping,” said Reyes, who played his first major league game since last May 20 yesterday after sitting out most of last year following hamstring surgery and then missing the first four games of the season this year rehabbing from a thyroid problem. “I thought it was in.”
Instead, Harris spoiled the 2010 debut of both Reyes and Oliver Perez, who was shaky in 5 2/3 innings.
Perez, coming off a dismal year and awful spring training, surrendered four runs yesterday — all driven in by Willy Taveras.
“He just ran into a guy who was really hot,” Jerry Manuel said of Perez’ performance against the usually light-hitting Taveras.
“It was very important to me get to 100 pitches,” said Perez, who threw 101. “My breaking stuff was working good and I was using all my pitches. It’s just frustrating to lose the game.”
That’s partly because the Mets also weren’t able to capitalize on numerous other chances — and also got shut down by former Yankee Tyler Clippard, who struck out seven in three scoreless innings in relief.
Still, both Perez and Reyes were encouraged by what they were able to do yesterday.
Reyes showed the rustiness one would expect from someone who hadn’t played in nearly a year, mishandling a slow Ian Desmond grounder in the fourth that was ruled a hit and led to a run.
He also somehow didn’t get an Ivan Rodriguez line drive hit almost directly at him in the sixth.
“Nothing happened,” said Reyes, who admitted to being nervous in the early-going. “I just missed it.”
But he recovered to make a nifty play in the top of the ninth on a grounder up the middle by Nyjer Morgan and then singled to lead off the bottom of the inning.
In the ninth, Manuel opted against having Reyes steal because it was his first game back, but Washington closer Matt Capps loaded the bases with walks to David Wright and Jeff Francoeur.
That led to Barajas’ shot to left, which Harris raced in to catch.
“Any loss is tough to take, but when you see victory close, it makes it even harder,” Barajas said.
Still, the Mets hope that Reyes’ return will wind up overshadowing this loss.
The shortstop arrived early yesterday, around 8:20 in the morning and received a standing ovation when he came up for the first time. But it wasn’t until the last inning that he really made his presence felt.
For now, Manuel said he will keep Reyes at the top of the lineup, but said that he would consider moving him to third as the season progressed.
“We’re just glad to have him back,” Francoeur said. “You saw what he could do out there in the ninth.”
Yesterday, though, it wasn’t enough.
dan.martin@nypost.com