If only college basketball games were 20 minutes,Maryland Coach Mark Turgeon had quipped earlier in the week, alluding to the challenge Illinois was bringing to Comcast Center with its enviable complement of big bodies.

As it played out, Turgeon couldn’t have been prouder of his Terps in the first half of Tuesday’s clash. For 20 minutes, Maryland dominated Illinois with tenacious defense, a furious rebounding effort and a crisply executed offense that alternated between patience and explosiveness, never trailing in the period after the Illini scored the opening basket.

But the Terps couldn’t sustain the effort, and Illinois pulled away for a 71-62 victory that snapped Maryland’s six-game winning streak in the Big Ten/ACC Challenge.

Once again, sophomore Terrell Stoglin led Maryland (3-3) in scoring, supplying a game-high with 25 points with his full-tilt assaults on the basket and often off-balance heroics from beyond the arc. Forward James Padgett added a career-high 16 points.

But the offensive discipline that served the Terps so well in the early going disintegrated once Illinois took the lead in the second half. Stoglin and freshman point guard Nick Faust (2 for 11, including misses on six three-point attempts) rushed their shots as the deficit grew.

Moreover, the Terrapins stopped racing back on defense. Their rebounding sagged.

Put-backs clanged off the rim instead of falling in.

And after pulling within one at 51-50, Maryland couldn’t stop Illinois from exploding for a 10-2 scoring spree that sealed the outcome.

Turgeon dismissed a suggestion that fatigue was a factor.

“I think it’s just toughness,” Turgeon said afterward. “Getting through it. Don’t let people take you out of what you’re doing. Run back on defense. Box out, which I’m all over them about.

“. . . We do not, right now at this point, know how to win against a good team. But we will. We’re making tremendous strides. And that was a good team that was well-coached.”

Illinois (7-0), which reached the NCAA tournament’s round of 32 last season, was the first quality opponent to visit Comcast Center this season, and 13,187 turned out to cheer the Terps on.

Illinois boasts an imposing front court anchored by 7-foot-1 center Meyers Leonard and 6-8 forward Tyler Griffey and brings three players off the bench who are 6-8 or taller, including a 6-11 freshman.

So Turgeon opened by going right at their strength.

He ordered plays for Padgett, the team’s most physical player. Padgett scored Maryland’s first six points, while a terrific collective effort on defense held Illinois to 28 percent shooting over the first eight minutes.

After Illinois tied it at 20 from the free throw line, Stoglin provided all the Terps’ points in a 9-3 run that followed.

Maryland took a 35-31 lead to the break, having shot 52.2 percent while holding Illinois to 40 percent.

It didn’t take long for Illinois to close the gap in the second half after a half-time lecture from Coach Bruce Weber.

“I know Turgeon’s teams, and they play their butts off,” Weber said. “Their big guys really got at us in the first half and hurt us. . . . The second half, we were much more aggressive.”

They also got a huge scoring assist from guard Sam Maniscalco (24 points), who drilled the three-pointer that put Illinois ahead with 14 minutes 16 seconds remaining.

And though Maryland had dominated all but one minute of the proceedings until then, the Terps started playing with a desperate air.

“We started rushing,” Padgett conceded. “We weren’t executing, and we missed a lot of free throws.”

Stoglin brought the crowd to life with a pair of three-pointers in the final minutes.

But from there, Illinois simply played keep away.

Said Stoglin: “We’re a young team with a new coach. Everything is new. We don’t want to make any excuse for why we lost today, but we’re learning.”