As Westfield junior Meghan Heick charged toward the net, she could imagine the game-winner in her head.

After fighting through a tough Oakton defense all night long, Heick found one of her few clear lanes to the Cougars’ goal Tuesday night and took it, netting the Bulldogs’ go-ahead goal midway through overtime to finally put Westfield up for good in a 12-10 victory in Vienna.

“They had been face-guarding me the whole game, so I wasn’t able to do as much as I could so I was just kind of frustrated,” Heick said. “I just took all the speed and energy that I had, and I wanted to get that ball into the goal so bad. I just took it, and I imagined it, and it happened, luckily.”

While the overtime proved fruitful for Westfield (5-0, 1-0 AAA Concorde District), it was the 10th-ranked Cougars (3-4, 0-1) who nearly won the game in regulation with a last-second goal. Oakton senior Catherine A. Miller found the back of the net for the go-ahead goal with just under 20 seconds left in regulation, But the goal was waved off by officials who ruled that Miller had stepped inside the crease.

“I thought it was over. I thought we were done,” Westfield junior Molly O’Sullivan said.

Heick’s game-winner was her third tally of the night, but the junior wasn’t the top offensive performer for the Bulldogs. That was O’Sullivan who did the bulk of the goal-scoring for Westfield, tallying six of her team’s 12 goals, four of which came in the first half.

Nearly all of O’Sullivan’s early goals came on set plays in which she curled around the left side of the Oakton goal just outside the crease. It’s a play the junior said she’s worked on for years.

“They say in girls’ lacrosse the crease is your best friend,” O’Sullivan said. “That’s just where I’m best I guess. Usually in the beginning of the game they’re not used to it so there’s no slides and you just go right on the crease, kind of use it as a pick, and just shoot.”

Heick and O’Sullivan combined to score nine of Westfield’s 10 goals , with the final tally coming off the stick of senior Colby Kidwell, who netted the insurance goal with less than 30 seconds remaining in the overtime. Miller was the top scorer for Oakton with four goals.

The win was especially sweet for Bulldogs Coach Katie Rusch, who was an assistant on the staff of Oakton Coach Jean Counts before taking the Westfield job in 2012.

“We lost to them twice last year and they were the state champs, so everyone’s always gunning to take down the state champs,” Rusch said. “We can’t celebrate for too long because our district is incredibly tough.”