For all the talk about Eric Floyd's jump shooting and Patrick Ewing's slam dunks, 17th-ranked Georgetown showed again yesterday that defense, at least for now, is the team's forte.

After a lethargic 25 minutes, the defense allowed the Hoyas to score 12 straight points that led to their 10th straight victory, a 75-58 decision over Robert Morris of Pittsburgh at Capital Centre before 7,155 fans.

Floyd, an all-America guard, led Georgetown with 22 points and Ewing, the freshman center, had 16. More important, Floyd and Ewing totaled 17 of the first 21 points the Hoyas scored in the second half.

Georgetown led at halftime, 31-28, as Chipper Harris, Robert Morris' 6-foot guard, scored 15 of his 21 points in the first 20 minutes. His 24-foot, fall-away jumper two minutes before intermission tied the game at 28.

Coach John Thompson said he told his team during intermission that, "We were sleepwalking out there."

It took a while for his team to wake up in the second half. The Colonials (4-5, all five losses coming on the road) answered Ewing's three straight baskets with field goals from Forest Grant and Tom Parks to stay within 40-36 with 14:24 remaining.

Then, the defense and Ewing took over.

Ewing received one of Eric Smith's 11 assist passes and slammed it in for a 42-36 lead. Freshman Anthony Jones (starting at forward in place of Mike Hancock, who had a slightly sprained ankle) blocked a shot that eventually allowed Ewing to stuff another for a 44-36 lead.

Harris' jumper over Ewing with 12:48 remaining provided the Colonials' last points until the 8:10 mark. Georgetown got 12 straight points.

Freshman forward William Martin, who played his best game of the season, took a rebound away from three Colonials and fed Jones for a basket. Floyd, after a turnover by the Colonials, lobbed a pass to Ewing for an easy score. Then Floyd stole the ball and fed Jones for a 52-38 lead with 9:47 left.

Robert Morris called time to break the momentum and figure out the various Hoya zones. But Smith spoiled any strategy by making a quick steal and scoring off a nifty return pass from Fred Brown.

Martin's basket, after Ewing's defensive play forced a turnover, gave the Hoyas a 56-38 lead, and the game for all practical purposes was over.

"Defense is what wins ball games," Smith said afterward. "And I think we're better defensively right now. We didn't pressure them in the first half and the game was close, but we did pressure them defensively the second half and the offense came around."

"Defense is the best part of our game right now," said Martin, who had seven rebounds and 10 points in 31 minutes. Jones, with 12 points and six steals, was another defensive star, frequently anticipating and stealing passes from men he wasn't guarding.

In previous games, the Colonials had relied on Harris, Grant and Parks for most of their points. Georgetown held Parks, the team's leading scorer, to six points and Grant to eight.

Despite the defensive performance in the second half, Thompson was disturbed because his team played so sluggishly at the beginning of its first game since two easy victories last week in the Rochester Classic.

"I don't why we were so lethargic," Thompson said. "We've already crowned ourselves the king of some domain that I don't know about yet. We've got to play a far sight better than that if we're going to do well against St. John's on Wednesday."