Terry Collins questioned himself before, during and after arguably his toughest decision ever as a manager.

The Mets manager was euphoric Johan Santana pitched the first no-hitter in franchise history, but still was not at peace letting his ace throw a career-high 134 pitches to do it — and that may lead to extra careful treatment going forward, including additional rest before his next start.

"I went against about everything I stand for," Collins said yesterday. "I kind of felt that I had made the wrong move."

Santana was making just his 11th start after missing more than a year because of a torn anterior capsule in his left shoulder. He is the highest-paid player in Mets history, in Year 5 of a six-year, $137.5 million contract.

"My whole thing was my heart told me to take him out due to the fact that I'm playing with a huge part of the organization," Collins said. "If this guy goes down, it'd be pretty drastic."