After playing as fine an offensive half as any basketball fan or coach would like to see, Georgetown again made a second-half collapse that is becoming all to frequent for its coach before beating St. Joseph's, 62-53, tonight.

"It's another situation in which I almost had a heart attack," said Georgetown Coach John Thompson. "Anytime we go in the locker room up by more than 10 points. I'm always scared to death."

Thompson had reason to be tonight at the Polestra, where his Hoyas, aggressive and prectise the first half, played passively and carelessly and let the Hawks creep within five points with 8 1/2 minutes to play.

However, as quickly as the Hoyas (10-3) seemed doomed, they regained their spunk and their wits. Jeff Bulis, who played extensively at center tonight, sank two free throws. Eric Floyd and Eric Smith surprised St. Joe guard Wayne Warwick with a double-team trap just past midcourt and stripped him of the basketball.

Star forward Craig Shelton, who had thrown away an inbounds pass as St. Joe pressed and rallied, atoned for that mistake. He missed a short jump shot but grabbed the ball off Boo Williams' fingers and canned the followup shot for a 49-40 lead.

When Mike Morrow fell victim to the half court trap and walked on St. Joe's next possession. The Hoyas would never lead by less than nine points the rest of the first game of this doubleheader.

Penn, one of the final four participants in the NCAA tourney last season, has lost two starters to injury and now starts two freshmen and two sophomores, but still defeated Temple, 59-46, in a Big Five matchup in the second game and evened its record at 4-4.

In the opener, point guard John Duran of Georgetown gave a seminar in how to attack a zone defense against a St. Joseph's team whose point guard, Luke Griffin, later said was more caught up in controlling the tempo to the slow pace it wanted than playing the opposition.

It was a fatal mistake. In a stretch of 17 possessions, Georgetown did not commit a turnover and converted 11 of 14 shots, either open jumpers or nifty inside plays as a result of Duren passes, and moved from a 4-4 tie to 30-14 control.

At 12-4, Duren connected on three straight jump shots, then assisted on Georgetown's next five baskets.

The Hoyas were alive at both ends of the court.They attacked both offensively and defensively, playing as much man-to-man defense as they have in the first half of any game this season.

"We had to do that," said Thompson. "We didn't want the kind of game we had with them last year (a 37-36 St. Joe upset). We were too conservative in that one. Offensively it was one of our smartest halves. We attacked at the right place."

For the second straight game, Georgetown reserves were prominent in buildings the big lead.Bullis, center Mike Frazier and Smith, who played twice as many minutes as Al Dutch did starting, all played well.

Georgetown went to the locker room with a 32-18 lead. Thompson was so "scared" at the start of the second half that he called a timeout before Georgetown's third possession, after the Hoyas missed two long jumpers and the Hawks scored twice from inside.

With St. Joseph's still in a zone, Duren again attacked it smartly, with successive alley-oop passes to Ed Spriggs and Shelton for easy baskets. At this point, St. Joe's threw its slow-game plans away, ordered a full-court press and man-to-man defense.

"We want people to play man-to-man," Thompson said. "But so many people have played zones against us . . . but we couldn't get any motion. We were standing around instead of getting the motion that we needed.

"It was a smart move on his part because it was the unexpected. And it was the thing that we wanted them to do. So much so that we thought they'd never do it."

"Rattled" was the way Shelton described the Hoyas, who had switched to a zone defense, watched Mike Morrow bomb away from the outside over it. Stopped attacking and committed turnovers on three of the next nine possessions. Suddenly, it was 45-40.

Before Bullis shot his free throws, set up by a Duren pass into the middle of a four-corners offense. Thompson called time out. "He wanted us to play smarter. We let the pressure get to us," said Bullis. "It was a lack of concentration."

In a bold move when a team wants to control the clock, Thompson put his team back in a full-court press. The reason, the coach said, "We had to make ourselves get back up. We got passive" The strategy worked and the Hoyas were helped when Morrow caught a finger in the eye with 5:59 to play and left the game.

Georgetown, as it had against Iona last game and hadn't in recent losses to Boston College and Drake, shot accurately from the fould line, hitting 10 of 13 in the second half tonight. But the players do not have an answer for why they have the psychological letdowns.

"That's something we have to work out among ourselves," said Shelton. "We're keeping our composure better than we had been. When they make a run at you, you have to keep playing the way you had been playing."