Williams finished 14-for-23 passing for 154 yards, one touchdown, and one interception. He also rushed for a touchdown in the first quarter.
The senior was at his best in his team's biggest drive.
Williamstown kicker Kevin Gilmore hit a 25-yard field goal to tie the score at 18 with 7 minutes, 28 seconds left in the fourth quarter.
On the next drive, Williams was 6 for 7 for 59 yards, hitting four receivers in a 64-yard drive that ended with Isaiah Austin punching in a go-ahead touchdown from 2 yards with 3:49 left.
The drive was a stark contrast to the flashy, big-play style Timber Creek has been known for this season, particularly due to big plays from Division I recruits such as receivers Adonis Jennings and Cameron Chambers.
"This win shows that [Williams] is one of the best quarterbacks in South Jersey, if not the best," Timber Creek coach Rob Hinson said.
Hinson was equally satisfied with the play of his defense, which held a vaunted offense in check, particularly running back John Chamberlin.
Chamberlin was limited to 86 yards on 27 carries, including a touchdown with 44 seconds left in the second quarter that cut Timber Creek's lead to 12-7.
"It was a great, physical game," Williamstown coach Frank Fucetola said. "They made the plays when they had to, and we didn't make the plays."
Timber Creek 6 6 6 7 – 25
Williamstown 0 7 8 3 – 18
TC: Dan Williams 1 run (kick failed)
TC: Adonis Jennings 27 pass from Williams (kick failed)
W: John Chamberlin 4 run (Kevin Gilmore kick)
TC: Isaiah Austin 1 run (pass failed)
W: Marquis Little 55 run (Devin Bradham pass from Doug Banks)
W: FG Gilmore 25
TC: Austin 2 run (Justin Gonzalez kick)