Gruber's interception in the end zone right before the half prevented the Cougars from taking a lead and momentum into intermission. Gruber later picked off a pass late in the fourth quarter to allow the No. 3-ranked Hawks (11-0) to run out the clock and advance to the quarterfinals for the first time since 2010.

"All the guys had been giving me a hard time for not having an interception this season," Gruber said. "I guess I picked the right time for them. I had to shut them up."

Maine South intercepted four Conant passes — three in the second half — to avoid losing in the second round for the second season in a row. Conversely, the Hawks didn't have a turnover on the afternoon.

Matt Alviti completed his final eight passes to finish 9-for-14 for 110 yards and a touchdown, a 37-yarder to George Sajenko to put the Hawks ahead 27-13 with 3:50 to go in the game. The Northwestern-bound quarterback also ran 21 times for 124 yards and two scores.

Maine South looked in control after Luke Durbin's 2-yard TD run at the 11:19 mark in the fourth that gave the Hawks a 20-7 lead, but Conant (7-4) responded with an 80-yard scoring drive, highlighted by Tim Manczko's 3-yard run.

The Cougars then recovered the kickoff, but they turned over the ball on downs. Five plays later, Alviti answered with the scoring strike to Sajenko for the two-touchdown advantage.

"After what happened last year, there was no way I was losing this game," Maine South junior safety Clay Burdelik said. "We came out and played with a different mentality. We are coming together, and I don't think anyone can stop us when we are rolling."

Maine South hosts Glenbard North at 1 p.m. Saturday in the quarterfinals. The No. 9 Panthers (10-1) beat Stevenson 23-14 on Saturday to win for the 10th time in a row.