The Chiefs’ usually cautious offense which hadn’t turned the ball over in the first three games was a turnover factory producing three Sunday against the Giants at Arrowhead Stadium.

Fortunately a dominant defense and Dexter McCluster’s punt return touchdown bailed out the Chiefs in a 31-7 win.

A bad shotgun snap in the second quarter — two plays after Tamba Hali sacked and stripped the ball from Eli Manning — ended the Chiefs’ streak without a turnover to start the season after 13 quarters.

During the third quarter Alex Smith threw his first two interceptions of the season but it didn’t matter as the Chiefs improved to 4-0 under Andy Reid thanks to the defense and special teams.

Clinging to a 10-7 lead late in the third quarter the Giants 0-4 appeared to convert a third-and-17 on a pass from Eli Manning to Victor Cruz but Reid challenged the spot and it was overturned.

Rather than go for it a half-yard shy from the Giants’ own 30-yard line Tom Coughlin sent out the punting unit and that touched off a rout.

McCluster spun away from long snapper Zak DeOssie as if he were a digital version of himself on Madden before slipping through a seam upfield and breaking into the open.

He juked past another Giants defender near midfield then raced untouched for an 89-yard touchdown.

It was the Chiefs’ first punt return score since McCluster’s 94-yard touchdown against San Diego on Sept. 13 2010 in the debut of the “new Arrowhead” on Monday Night Football.

After a Giants punt Smith connected with Jamaal Charles on a 2-yard touchdown pass — capping a 14-play 80-yard march that broke New York’s back and took more than 9 minutes off the fourth-quarter clock.

On the Giants’ next drive Eric Berry scooped up a Da’Rel Scott fumble and set up a short field.

Three plays later Smith drilled a deep slant to Bowe who broke two tackles and trotted to the end zone for the game’s final score.

Neither offense put points on the board in the first quarter but the Chiefs scored on the third play of the second quarter.

Smith capped an impressive 11-play 98-yard march with a 5-yard touchdown to McGrath who eluded his defender in the back of the end zone for his first NFL score.

That lead didn’t hold up very long.

Cruz roasted Chiefs cornerback Dunta Robinson who started in place of injured Pro Bowler Brandon Flowers on a go route up the sideline and knotted the game at 7-7.

Both teams got a bit sloppy from there.

Manning fumbled when he was sacked by Tamba Hali.

Robinson fell on the ball for the Chiefs but two plays later Rodney Hudson’s shotgun snap never made it to Smith.

Linebacker Spencer Paysinger pounced on the loose ball when it squirted free for the Chiefs’ first turnover of the season.