NEW YORK — Even after building a 20-point lead, it’s not as if everything Georgetown attempted against the badly misfiring Texas Longhorns turned to gold Tuesday at the Jimmy V Classic.

Sharp-shooter Greg Whittington missed jumpers he normally knocks down. Sophomore center Mikael Hopkins had more fouls than baskets and rebounds combined. And too many possessions were squandered by careless passes and traveling calls.

But for nearly every error on offense, the Hoyas raced back to atone for their gaffes by doubling down on defense, making a young Texas team look woefully outclassed at Madison Square Garden.

The result was a 64-41 victory that improved No. 15 Georgetown to 6-1 and revealed what may prove its most promising quality this season. While not yet polished, the Hoyas showed themselves to be a hard-working bunch that doesn’t take defensive plays off, doesn’t take leads for granted and doesn’t consider itself a finished product.

“I think that’s what makes this very exciting — the fact that we can get a lot better,” said junior forward Nate Lubick, who scored a career-high 13 points on 6-of-7 shooting, showing no ill effects from an elbow injury suffered against Tennessee last week. “There are a lot of things we can sharpen up on, on both sides of the floor.”

Sophomore Otto Porter Jr. set the standard in full-court persistence, finishing with a game-high 14 points while contributing eight rebounds, three blocks, three steals and two assists.

“The team and the coaches want me to be aggressive,” Porter said, “and that’s one thing I wanted to pick up coming into this year.”

While Georgetown is young, starting two juniors and three sophomores, Texas (5-3) is even younger and playing without starting point guard Myck Kabongo, who is being held out pending an NCAA probe into whether he received improper benefits. That reduced Coach Rick Barnes’s starting lineup to two sophomores and three freshmen.

They combined to miss their first six shots, and Georgetown bolted to a 9-0 lead.

The Hoyas never trailed, padding their lead to 17 midway through the first half. And when Texas pulled within eight four minutes into the second half, Georgetown went on a 12-2 run that put the game out of reach.

The final statistics were grim for the Longhorns, who elicited a smattering of boos from some of their fans at Madison Square Garden during their nearly 10-minute scoreless span.

Texas made just 14 field goals in the game (and only six in the second half) while turning the ball over 22 times. The Longhorns shot 29 percent as a team; their starting guards were worse, hitting just two of their 14 attempts.

Texas reserve Sheldon McClellan (12 points) finally got the scoring going with a three-pointer. Through the first 10 minutes 46 seconds of play, McClellan was the only Longhorn to score.

Meanwhile, with his Hoyas in reasonable command, Georgetown Coach John Thompson III gave his reserves some playing time, bringing 6-foot-9 junior center Moses Ayegba in for Hopkins. By game’s end, 14 Hoyas got playing time, with freshman D’Vauntes Smith-Rivera, Jabril Trawick and Stephen Domingo getting the most experience.

Lubick handled the ball with authority and stood up well to the Longhorns’ shot-blocking freshman center, 6-9, 270-pound Cameron Ridley.

With a three-pointer by Smith-Rivera, Georgetown extended its lead to 26-9.

But Texas closed the half on a 6-2 run, paring Georgetown’s lead to 30-17 at the break.

Texas defended better to open the second half, and cut the Hoyas’ lead to single digits, 32-24, on a three-pointer by McClellan.

Markel Starks replied in kind, spurring the run that restored what had been an 18-point lead.

“We are a work in progress,” Thompson said. “I think that we’re going to be much better than we are right now. But with each passing day, the group is feeling a lot more confident.”