Terry Collins took full responsibility for the whiplash suffered by Johan Santana last night at Yankee Stadium.

The Mets manager could have used his ace on regular four days' rest after Santana threw the first no-hitter in franchise history last Friday.

Concerned the stress and elevated pitch count had taken a toll on Santana's surgically repaired left shoulder, Collins opted to give Santana six days of rest before last night's Subway Series opener against the Yankees at Yankee Stadium.

"I was responsible for the way he pitched tonight,'' Collins said. "He was rusty. That's my fault.''

Unable to throw his breaking pitches for strikes, Santana was punished for leaving fastballs above the belt and gave up four homers — three consecutive in the third inning — on the way to a 9-1 beating in front of a sellout crowd of 48,566.

In five frames, Santana (3-3) gave up six runs and seven hits and was constantly snapping his neck to follow the flight of the four homers.

"Every mistake he made he got hammered,'' Collins said.

The first of two Robinson Cano homers came in the second. Cano, Nick Swisher and Andruw Jones went back-to-back-to-back against Santana in the third.