BLOOMINGTON, Ind. -- Indiana coach Tom Crean challenged his team to be tougher than Illinois on Thursday night.

When it mattered most, they were.

Cody Zeller and Victor Oladipo repeatedly drew fouls, did much of the damage inside and combined on a late scoring frenzy to send No. 23 Indiana past Illinois 84-71.

"You have to execute under pressure, that's one of the greatest forms of toughness you can have," Crean said. "But you have to be able to play through contact as well."

Indiana (19-6, 7-6 Big Ten) excelled in both facets, putting Crean one victory from his first 20-win season since leaving Marquette for the Hoosiers in 2008.

The biggest reason for this season's remarkable turnaround, of course, has been the inside presence of Zeller and he was up to his old tricks against the Fighting Illini (16-8, 5-6).

It was clear coach Bruce Weber wanted to outmuscle Indiana's freshman center. Instead, Zeller made nifty move after nifty move and drew foul after foul. He finished with 22 points, five rebounds and went 5 of 8 from the field and 12 of 14 from the free throw line.

"I think if you're going to get physical with him, he's going to respond," Crean said. "The only soft thing about Cody is that he's soft-spoken on the court sometimes, but other than that he's a tough, tough person."

Zeller had plenty of help, too

Oladipo and Christian Watford had 18 points and Jordan Hulls finished with 15 points and seven assists.

Indiana used an 8-0 run to finally break open what had been essentially a one-possession game for the first 24 minutes. Then the Hoosiers used a 15-6 run to pull away.

For Illinois, it was another devastating blow in a season filled with disappointments. The Illini have lost five of six and have dropped five straight in Bloomington when Indiana has been ranked, a streak that dates to 1997.

"We played our butt off, we played some good basketball, we've done it all year. We're close," Weber said. "We've just got to see if we can connect it all together. Somewhere here, we'll get everybody playing well, get offense and defense clicking at the same time without fouling, without turning it over. That's the key."

That didn't happen at Indiana.

While D.J. Richardson scored 19 points and Meyers Leonard had 17, Brandon Paul, the Big Ten's No. 9 scorer, connected on just 4 of 11 shots and finished with 13 points.

The Illini committed 30 fouls and had three players, including Leonard, foul out.

"The refs called good fouls, we made some stupid fouls in the first half," Richardson said. "We've got to do a better job attacking the basket. Their guys did a great job of that."

For nearly 19 minutes, the teams traded possessions and baskets and from the time Indiana blew a 13-6 lead until early in the second half, neither team led by more than four points.

Indiana finally ended the tug-of-war with a quick scoring flurry early in the second half.

Hulls' 3-pointer broke a 46-46 tie. Zeller then drew a foul on a dunk and completed the three-point play to give Indiana a 52-46 lead. After Watford grabbed a loose ball and called time out, Zeller drove in for a layup to make it 54-46 with 15:24 to play.

"We were in the bonus pretty early, so I definitely wanted to attack," Zeller said of the Hoosiers' second-half surge. "Any foul was going to be one or two free throws, so I definitely wanted to be aggressive and get to the free throw line."

Illinois responded with 3s from Paul and Richardson on consecutive possessions. Paul followed that with a layup, then hit 1 of 2 free throws to get the Illini within 57-55 with 10:58 to go.

With Illinois within 62-59, Zeller and Oladipo changed the equation by drawing fouls.

They combined to make 5 of 6 free throws, starting the late 15-6 run that gave Indiana a 77-65 lead with 4:49 to go.

Illinois didn't get closer than 10 points the rest of the way.

"Our guys came out and played with a ton of intensity," Crean said. "Our guys, they deserved it. It was a hard-fought game and they deserved it because they played hard the entire way."