Thomas scored a season-high 28 points and Simmons added 23 to lead Holy Cross to a 74-66 victory over Bucknell on Friday that gave the Crusaders their fifth Patriot League championship and an automatic berth in the NCAA Tournament.
"To play our last game here and have this result is unbelievable," Simmons said.
Bucknell erased a 19-point second-half deficit, but Holy Cross converted 16 straight free throws in the final five minutes to secure the win.
"I knew Bucknell was not going to die because all our games have gone down to the wire," Crusaders coach Ralph Willard said. "I have never coached two betters kids [Simmons and Thomas] in my entire life and I couldn't be happier."
Holy Cross (25-8) won its fourth championship under Willard but the first since winning three straight from 2001-03.
Bucknell represented the Patriot League well in the last two NCAA Tournaments, with first-round wins against Kansas in 2005 and Arkansas last season.
"We've been in three NCAA Tournaments and we had opportunities to win all three games against Kansas, Kentucky and Marquette," Willard said. "Defense will give us the opportunity to win against teams that are more athletic."
John Griffin scored 15 points for Bucknell (22-9), which had knocked out the Crusaders three straight years, including in the last two championship games.
"No one can take away how hard we played," Bison coach Pat Flannery said. "I am looking forward to rooting for Holy Cross."
The loss snapped Bucknell's 14-game winning streak. Earlier this season, Holy Cross beat Bucknell and ended the Bison's 23-game winning streak against conference foes.
Holy Cross opened up the second half with an 11-5 run to increase its lead to 46-27 before Bucknell responded with a 13-0 run over a span of 5:32 to get to 46-40.
Donald Brown pulled Bucknell to 51-49 when his dunk followed a missed layup by Justin Castleberry. Darren Mastropaolo tied the game at 53-53 with 5:52 remaining, but Holy Cross scored seven straight, capped by Thomas' 3-pointer, to go ahead 60-53.
Holy Cross won 18 of its last 20 on the way to the title.
After falling behind 14-11, the Crusaders went on a 21-4 run keyed by eight points from Patriot League player of the year Keith Simmons. Bucknell shot 27 percent in the half and was stymied by the Crusaders' defense, which held the Bison without a field goal for 9:08.
Bison coach Pat Flannery has won a conference-record 18 tournament games. ... The Bison's 14-game winning streak was the longest in school history. ... Tim Clifford registered six blocks in the first half.