On the surface, the math looked funky.

The Ridgefield High boys tennis team won three matches during a 7-0 victory over Westhill in an FCIAC quarterfinal contest Friday at the RHS courts.

Actually, the third-seeded Tigers could have still advanced to Monday's semifinals against second-seed Greenwich without winning any matches.

The explanation had to do with Westhill's social calendar: The Stamford school was having its senior prom Friday night, and the result was that the Vikings sent just four players to Ridgefield for Friday's match — even though the host Tigers had bumped up the start time from 4 to 2:30 to help accommodate Westhill.

The absences led sixth-seed Westhill to forfeit at third and fourth singles and second and third doubles, giving Ridgefield the four points needed for a victory.

But the Tigers made it a 7-0 sweep by winning the three matches that were played.

Ridgefield, which improved its record to 14-3, got straight-set triumphs from Brian Song (6-2, 6-0) at first singles, Ramiro Dávila (6-0, 6-2) at second singles, and Tanner Daubenspeck and Noah Butler (6-0, 6-0) at first doubles.

Notes: Ridgefield had beaten the full Westhill squad by a score of 6-1 during a regular-season match on May 10. Six Westhill players who had competed in that match did not make the trip for Friday's quarterfinal.

Monday's semifinal is scheduled to start at 4 p.m. at Greenwich High School.

Greenwich advanced to the semifinals with a 4-0 victory over seventh-seed Fairfield Ludlowe on Friday.

The Ridgefield-Greenwich winner meets either top-seed Staples or fourth-seed Darien in the conference finals on Wednesday at Wilton High School. Darien travels to Westport to play Staples in the semifinals on Monday.