Stanford pulled to within two of top-ranked USC midway through the third quarter, but the Trojans scored four of the game's final five goals to beat the No. 3 Cardinal women's water polo team, 8-3, on Saturday afternoon at Avery Aquatic Center.
The loss, which snapped Stanford's eight-game win streak, was also the Cardinal's first regular-season league defeat since 2009. Stanford (19-3, 4-1 MPSF) had won a conference-record 43 consecutive MPSF contests.
The deficit was stretched back to three when Stephania Haralabidis scored her first of two third-quarter goals less than three minutes into the period. A double exclusion followed by another whistle on Stanford gave USC a 5-on-4 opportunity and Haralabidis' attempt was blocked and deflected into the cage near post past Julia Hermann.
Kat Klass made it 4-2 on Stanford's next possession. From inside, Shannon Cleary passed it back up top to Jamie Neushul. Neushul lobbed it far post to the Cardinal freshman who guided it in with 4:55 remaining in the period.
Haralabidis put home another power-play goal at 2:38, going top shelf from five-meters out.
Stanford had a few additional chances in the third. At 2:13 Klass' shot was tipped and deflected off the bar and at 1:11 her skip shot was tipped and saved by Longan. Early in the frame, Gurpreet Sohi fed Katie Dudley inside at two-meters, but Dudley's back-handed attempt hit the bar and bounced out.
Brianna Daboub (7:26) made it 6-2 USC early in the fourth quarter and Hayley McKelvey completed her hat trick with 6:34 left in the game on a lob up and over Hermann.
Jordan Raney, sitting to the left of the cage, scored from five-meters with 5:26 to go for her 16th goal of the season.
Julia Hermann made seven saves for Stanford, which was also unable to convert its man-up chances, going 0-for-7.
Seniors Rachel Johnson, Gurpreet Sohi and Anna Yelizarova were honored in a pregame ceremony. The group has led Stanford to a 98-9 record and a pair of national championships during their time on The Farm.
The Cardinal concludes its regular season next Saturday at No. 2 UCLA at 11:30 a.m. in a game televised on Pac-12 Bay Area and Pac-12 Los Angeles.