Overview: No. 10 Gonzaga (9-1) confirmed every perennial doubt about its ability to compete with more athletic and versatile squads from power conferences. No. 13 Illinois proved that it can compete with elite teams, even on the road. This was a big victory in John Groce’s first season. His team was down by double digits early but recovered. It was the Illini’s first nonconference road win over a top-10 opponent since 1986 against Georgia Tech. The Bulldogs led 12-3 in the first three minutes of the game, but the Illini clamped down defensively and ended the half tied at 41. Gonzaga didn’t react well to its opponent’s defensive physicality. And it completely lost Brandon Paul (35 points), who was option A, B and C for the Illinois offense. The Zags couldn’t quiet him, no matter what they tried. In the end, Paul made plays that helped the Illini separate down the stretch.

Turning Point: This game was played in waves. Gonzaga led 31-20 with 8:18 to go in the first half after Kevin Pangos hit a 3. But the Zags made just one more field goal for the rest of half as Illinois forced six turnovers during that stretch and closed that gap. But this game never felt completely settled until Paul turned a four-point game into a seven-point advantage for the Illini when he drove and drew a foul on a Kelly Olynyk with 2:29 to go to put them ahead 78-71.

Why Illinois won: The Illini won in part because they shook off an early funk and got serious on defense. But really, Paul exploded. He was clearly the difference in the game. He was better than everyone on the floor. But the Illini also deserve credit for their defensive effort. With 10 minutes to play, Gonzaga was shooting 40 percent from the field in the second half, a major difference from the first half when it shot 61 percent from the floor. Paul’s effort was critical for the Illini’s improvement.

Why Gonzaga lost: The Bulldogs looked content to coast after their quick start. Illinois adjusted and Gonzaga mishandled possessions and missed shots. The 16 turnovers, their second-half shooting slump and Paul’s performance were just too much for them to overcome.

Star of the game: Paul. It was his night. He had 35 points (10-for-16, 10-for-11 from the free throw line), 4 rebounds, 3 assists, 3 steals and 2 blocks.

What it means for Illinois: It’s too early to know. It was a great win for the program. The Illini beat a tough Gonzaga squad on the road in front of a raucous crowd. But they did it with an uncanny effort from Paul. He won’t play like every night. To compete throughout the rugged Big Ten season, they have to win on Paul’s ordinary days, too. I think there’s reason to be excited in Champaign. And Groce deserves credit for what he’s achieved so far. But it’s not time for an over-the-top celebration quite yet. Illinois has to prove that it can win high-caliber games when Paul doesn’t play out of his mind.

What it means for Gonzaga: It means the Zags have to get tougher. That’s always the story. They weren’t tough enough mentally or physically. They were at home and an Illinois team that essentially relied on one player bounced back from a double-digit deficit to win by double digits. That shouldn’t happen. But the Zags looked soft on defense. They play Kansas State and Baylor in the coming weeks. Similar defensive efforts will lead to similar results, I assume.

What’s next: The Illini return to Champaign for their next two games. They’ll play Norfolk State on Tuesday and Eastern Kentucky next Sunday. Both are tune-ups for their Dec. 22 matchup against No. 12 Missouri in St. Louis. Gonzaga will face Kansas State (Dec. 15), Campbell (Dec. 19) and Baylor (Dec. 28) in its next three matchups.