With 1:25 left, Ariel Braker got a steal off an inbounds play for Oregon State, and McBride sank a jumper to make the score 66-58. Braker blocked Weisner on the Beavers' next possession.
Weisner, a sophomore guard, entered the contest as the Beavers' top scorer with 14.9 points per game. Oregon State has a young team, with four underclassmen starters.
The Beavers were coming off a 74-41 win over Clemson on Dec. 21.
In the Beavers' only other matchup against a ranked team so far this season, they lost 61-56 to then-No. 13 Penn State on Nov. 29.
The Beavers' last win against a ranked team was in 2003, and its most recent win against a top 5 team was in 1992.
Sunday's game was the start of a tough stretch for Oregon State, which opens Pac-12 play next week with games against No. 23 California and No. 4 Stanford.
"How does it get better than this?" Rueck asked. "We play in one of the best conferences in the country, we're young and all that. I don't care. I mean, I feel like we can win every night."
Sophomore Jewell Loyd, last year's national freshman of the year, came into the game leading the Irish by averaging 18.5 points and 7.1 rebounds per game. She scored 10 on Sunday.
The Irish reached the Final Four the last three years, and played for the championship in 2011 and 2012. This is Notre Dame's best start since 2009-10, when the Irish began 15-0.
Notre Dame's next game is Jan. 2 against South Dakota State.