NEEDHAM – The unbeaten Needham football team is built to flourish in the rain, and the historic Frederick J. Gorman Centennial Trophy stays with the program for a second straight year to prove it.

Behind a shutout opening three quarters and another huge stat line from star senior Aidan Williams (173 rushing yards, two touchdowns), the Rockets (12-0) outlasted Wellesley, 20-13, despite rain-soaked conditions in the 137th Thanksgiving Day matchup between the country’s two oldest public-school rivals.

Needham still has more football to play in the Div. 1 Super Bowl at Gillette Stadium next Thursday against Xaverian, but there’s no mistaking the significance of the Thanksgiving Day win – the program’s fourth in the last 10 years.

The Raiders (8-4) still hold the overall lead in the series at 66-62-9.

“The Super Bowl is amazing, the Super Bowl is great,” said Needham head coach Doug Kopcso. “We’re excited for that. That’s a once in a lifetime, I guess for us a twice in a lifetime opportunity. But the Wellesley game, it’s something that 20 years from now, everybody’s going to ask, ‘How did it go?’ So, for these guys to be able to start wrapping up their senior year with a victory over Wellesley – two in a row – is a big, big deal.”

“It means everything,” Williams added. “Everything to the team, everything to the coaches, everything to the program. Everything to the town, especially. … I mean, turkey always tastes better after you beat Wellesley.”

Rain gradually fell heavier as the game progressed, which – along with some costly penalties – aided both defenses in a low-scoring first half filled with short gains and third-down stops.

Williams had just 33 of Needham’s 97 rushing yards in the first half on half of its 24 carries, but the offensive line paved room to run in the second half. That included a 35-yard touchdown run he broke one tackle on to extend the Rockets’ slim halftime lead to 12-0 with 2:06 left in the third quarter, which also putting him over 100 rushing yards on the day.

“It was really just the O-line blocking up front, that’s the way it’s been all year,” Williams said. “We play a very physical brand of football. Obviously, it’s great for this weather. We love the rain. … Really, just playing gritty football.”

Needham’s defense held Wellesley without a first down for nearly two quarters since moving the chains twice in its opening drive, anchored by sacks from Jack Dufort and Caden McNamee, and a Ben Schreiber interception. It also wasn’t until 2:46 remained in the game that Wellesley finally got on the board.

Needham’s Griffin Carr looks to make a pass during the Thanksgiving day game at Needham High School. (Libby O’Neill/Boston Herald)

“Our defense, we hunt,” Kopcso said. “Our guys are relentless. … Our guys, they didn’t quit. They kept hustling to the ball, that’s a talented team that they played there.”

The Raiders put up a good fight behind quarterback Lukas Prock, who nearly salvaged the team’s slow offensive day with a comeback. Prock’s deep strikes to Matthew Liebman (four receptions, 66 yards) set up his 8-yard touchdown pass to Tennyson Charney to cut the deficit in half with 2:46 left. Later on, he connected with Charney again for a 4-yard touchdown pass with 13 seconds left.

But it came well after Williams ripped off a 59-yard touchdown run to ice the win on the first play of its drive following the Raiders’ first score.

“The unicorn,” Kopsco said of Williams. “The unicorn is going to play like a unicorn. He’s got that other gear.”

Brandt Bickford also scored a touchdown for Needham on a 5-yard pass from Griffin Carr in the second quarter.