In the first inning last night, Oliver Perez reached 95 mph. In the fifth, he struck out Alfonso Soriano with a 93 mph fastball.

But those impressive heaters may have led to Perez running out of gas as the left-hander failed to hold on to a 5-1 lead in a devastating 9-6, 10-inning loss to the Cubs last night at Shea. Perez, who couldn’t last five innings, hurt the Mets’ chances of playing postseason baseball next week. The Mets are tied with the Brewers for the wild-card lead and are 1 ½ games behind the Phillies in the NL East.

“Ollie was more power than pitcher tonight,” manager Jerry Manuel said. “When you feel good and get all geeked up sometimes, you can get away with that to a certain degree. But that doesn’t fare very well against good teams. You’ve got to pitch. The good teams make the adjustments, and that’s what they did tonight.”

Perez surrendered five runs in 41/3 innings, giving up six hits and walking five.

Perez said he was disappointed in his outing.

“I didn’t do my job,” he said.

Perez put the Mets in a 1-0 hole in the second on Mark De Rosa’s homer. After the Mets went ahead 5-1 going into the fifth, Perez loaded the bases, and served up a two-run double to De Rosa, cutting the lead to 5-3. Duaner Sanchez relieved Perez and promptly gave up a two-run, game-tying single to Reed Johnson.