Time was running out for host Mundelein on Saturday afternoon as the top-seeded Mustangs faced No. 2 Stevenson in the Mustangs' own girls water polo sectional.
Mundelein trailed 5-1 at halftime and 5-2 after three periods. But the Mustangs never panicked in the championship match against the Patriots.
Mundelein (23-6) methodically put together a big comeback behind some great defense and timely scoring en route to an exciting 6-5 victory for the sectional crown.
The Mustangs will face Barrington in the Elite Eight quarterfinals Thursday at 5:45 p.m. at Stevenson while the Patriots closed out their season with a 25-8 record.
Goals by Stevenson's Allison Travetto and Brittany Gartenberg in the final 48 seconds of the opening quarter staked the Pats to a 2-0 lead.
Then teammates Alex Kanaris and Melissa Gartenberg added goals early in the second quarter and the Patriots held a 4-0 advantage.
Junior Karrie Kozokar broke up Stevenson goalie Becky Callen's shutout with 3:35 left in the first half on an assist by Kasia Wienckowski.
But the Patriots' lead went back to 5-1 late in the second quarter as Travetto's shot hit Mundelein goalie Anna Ward's hand before going into the net.
Callen wound up with 15 saves, but Ward and the Mustangs' defense was flawless in the second half.
"It was one of those games, we had to score in the second half and we didn't score," said Stevenson coach Jeff Wimer. "Kudos to Mundelein, they outscored us 5-0 in the second half and you have to play four quarters to win."
Allie Boothe started the Mustangs' dramatic second-half comeback as her goal with 1:33 left in the third quarter cut the lead to 5-2.
Then Boothe scored her second goal from close range to cut the gap to 5-3 with 5:01 to play.
A fastbreak play from Ward to Boothe made the score 5-4 with only 1:53 remaining.
The Mustangs scored the tying goal with 49 seconds to go as Wienckowski's shot found the right corner of the net.
And then with just 17 seconds left, Wienckowski assisted Kozokar, who scored the game-winner from close range to put Mundelein in the Elite Eight for the first time since 2010.
"Our team just kept fighting through it and in the end things started going great for us," said Kozokar. "Playing smart and using the time we had left to our advantage was the key."
Ward had some nervous moments in the net, but she was able to keep her composure to help preserve the narrow victory.
"I started to get worried, but I told myself not to give up," Ward said. "We all put more effort into it than ever before and we're going to make it to the final four. We believe in ourselves and we know we can do it."
Mundelein coach Drew Schneider was very happy with his teams' late-game heroics.
"All year they've been spectacular in believing in themselves and finding a way to win, and they are excellent at persevering," said Schneider. "Our shots just weren't falling in the first half, but we were getting good looks at the goal. I want to give their goalie (Callen) credit. She had a spectacular game and our goalie (Ward) played great. It was a defensive battle."
Mundelein senior Courtney Perreault will head to state with the Mustangs' squad while twin sister Marisa reached state in track as a member of the 4 x 800-meter relay team.