This was truly a day for La Salle to celebrate.

The 17 seniors on the Explorers' lacrosse team graduated yesterday. After the ceremony, those players and their teammates faced Downingtown East in the biggest game of the season. And a couple of hours later, La Salle had something other than graduation to rejoice about.

The Explorers defeated the Cougars, 10-8, in a PIAA state quarterfinal at Harriton High School.

The victory sent La Salle (19-4) into the semifinals Tuesday at a neutral site. The District 12 champion will face the winner of last night's game between District 3's top seed, Manheim Township, and District 7's No. 1 seed, Mount Lebanon.

Downingtown East, the second seed in District 1, finished the season at 20-4.

"To celebrate a graduation and win a game all in one day is great," said La Salle senior goalie Niko Amato, whose squad is ranked first in the state by Phillylacrosse.com.

The Explorers are 30th in the nation, according to Laxpower.com's computer rankings. Downingtown East is ranked fifth in the state by Phillylacrosse.com.

Perhaps still thinking about the morning's graduation, the Explorers had a few lapses during the game. Senior attackman Pete Schwartz and sophomore attackman Kevin Forster finished with three goals apiece, but La Salle trailed early and gave up four unanswered goals in the fourth quarter.

None of that matters to Amato.

"We just sent one of the best teams in the country home for the season," he said of the Cougars, who were ranked 48th nationally in the Laxpower.com computer rankings. "We don't care about style points."

At one point, it looked as if La Salle would be the team sent home.

Downingtown East junior attackman Shane Sturgis' second of four goals gave his team a 3-1 cushion with 3 minutes, 21 seconds remaining in the first quarter.

Showing grit, La Salle battled back to twice knot the score. The second time came when Forster's second goal made it 4-4 with 8 minutes, 54 seconds left in the half.

The Explorers had a 6-4 cushion after back-to-back goals by Schwartz.

Then a goal by senior attackman Westy Hopkins gave La Salle a 7-4 lead late in the half.

With 4:18 to play in the third quarter, the Explorers had a 10-4 advantage. Downingtown East, however, scored the four goals in the fourth quarter to pull within two.

La Salle 3 4 3 0 - 10

Downingtown East 3 1 0 4 - 8

Goals: LS-Pete Schwartz 3, Kevin Forster 3, Derek Bogorowski, Westy Hopkins, Randy Forster, Patrick Resch. DE-Shane Sturgis 4, Kenny Maas 3, Mason Poli.

Saves: LS-Niko Amato 11. DE-Matt Normoyle 7.

Contact staff writer Keith Pompey at 610-313-8029 or kpompey@phillynews.com.