Dave Scanlon bounced over, around and through No. 1 St. John's to the tune of 149 yards and two touchdowns to lead No. 2 De Matha to a 21-13 come-from-behind triumph in the Metro Conference football opener for both teams yesterday at St. John's.

The hard-running 5-foot-10, 160-pound senior, who lugged the ball 33 times, 10 in a row at one point, was not only hero for the Stags (6-0), who ran 65 plays to St. John's 32 and totaled 333 yards on offense.

Flanker-safety Gil Hoffman, who misplayed a pass that went for a St. John's touchdown, vindicated himself with a key interception and the gametying touchdown.

Hoffman's seven-yard scoring pass from Dennis Boucher capped a 16-play, 84-yard drive. Mike Seddon's second of three conversion kicks put De Matha ahead to stay, 14-13, with 2:33 left in the third quarter.

"Their second touchdown was my fault, just a bad play," said Hoffman. I went for the interception instead of going through my man."

On first down from the De Matha 41, Ray Daly, who completed seven of 12 passes for 170 yards, fired a pass down the middle for Dave Waldron, who had circled out of the Cadet backfield. Hoffman appeared in good position for an interception, or at least a defletion, but made neither, and Waldron grabbed the ball at the 20 and scored untouched, giving St. John's a 13-7 lead.

The conversion failed, but St. John's (5-1) was ahead with 38 seconds left in the half.

Seconds later, an apparent score on a 55-yard pass reception by De Matha's Derek Carter was nullified by a holding call.

De Matha got a quick start in the third quarter, however. On the second play, Hoffman leaped in front of Cadet receiver Richard Gray and intercepted a Daly pass at the De Matha 16. What seemed like an hour later, Hoffman sneaked into the corner of the end zone and waved his arms frantically until Boucher spotted him and threw the touchdown pass.

DeMatha's other heroes wore high numbers. The offensive linemen opened huge holes for Scanlon and the other De Matha backs. De Matha rushed for 128 yards in the second half, while Boucher, who De Martha Coach Jerry Franks said didn't need to throw, completed all four of his second-half tosses for 60 yards.

"We ran nothing but straight-ahead dive plays and sweeps," said Scanlon. "The line just did a fantastic job."

"Not to be outdone, the De Matha defensive line limited the Cadet running attack to two yards and sacked Daly four times.

Following a Mike Johnson sack on a fourth down, De Martha went 62 yards for its clinching touchdown. Scanlon, who carried on five of the 10 plays, shook off two would-be tacklers as he weaved up the middle from nine yards out.

De Matha jumped on the board first after recovering an onside kick on the opening kick-off. Scanion bolted over from three yards out and Seddon added the kick to put the Stags up, 7-0, with 7:46 left in the quarter.

The Cadets, mainly on a 65-yard pass from Daly to Gray, went 75-yards in five plays to tie the game. Waldron scored from a yard out and Mike Bedford added the kick.

St. John's then grabbed the lead as Waldron outfoxed Hoffman on the 41- yard scoring play.