LOS ANGELES -- Second-ranked Stanford avenged the only blemish on its slate Saturday, handing No. 1 USC its first loss with a 6-4 decision at Uytengsu Aquatics Center.

The win clinches the top seed for Stanford (24-1, 5-0 MPSF) at the MPSF Championship. As the top seed, Stanford owns a first-round bye.

Goalie Kate Baldoni made eight saves in the contest, while Annika Dries made multiple field blocks to lead another sterling defensive effort by the Cardinal. USC entered the game averaging more than 15 goals a game and its four goals Saturday were a season-low for the Trojans.

Melissa Seidemann led the Cardinal with a pair of goals, while additional goals were scored by Kaley Dodson, Ashley Grossman, Kaitlyn Lo and Maggie Steffens.

Seidemann set the tone for the Cardinal right away, netting a goal on each of Stanford's first two possessions. The Cardinal lead stretched to 3-0 on Maggie Steffens' counter, but Colleen O'Donnell pulled one back for USC (20-1, 4-1 MPSF) before the end of the frame.

The Cardinal defense continued to dig in as the second period went on, holding the Trojans scoreless and killing off 6-on-5 situations during the eight-minute span. On the other side of the pool solid passing from Kiley Neushul and Steffens sprung Lo for the period's only goal and a 4-1 halftime lead for Stanford.

USC opened the second half with some good looks at goal, but still had no answer for Baldoni and the Cardinal defense. Stanford put even more pressure on the Trojans as Grossman found the back of the net to swell the Cardinal lead to 5-1. Anni Espar pulled it back for the Trojans minutes later just as the Cardinal was coming back to even strength from a 6-on-5 and the period ended with the Cardinal again up by three.

The Trojans struck first in the fourth frame, as Madeline Rosenthal drew a five-meter penalty that was converted by Espar with four minutes to go. Yet the Cardinal refused to keep the door open for a Trojan comeback, slamming it shut on Kaley Dodson's perimeter shot, making it 6-3. USC got a 6-on-5 goal from Monica Vavic with 34 seconds left but Stanford ran out the clock and claimed the important victory.