San Diego Christian (3-11-1, 1-7) tied it in the 78th minute, before O'Brien converted an assist by Edgar Hernandez.
Orange Coast 3, Riverside 0
COSTA MESA — Chase Nugent scored twice for the host Pirates in the Orange Empire Conference game Tuesday.
Thales Serra added a goal for OCC (9-6, 5-4 in conference), for which Tyler Folkins had six saves to post his third straight shutout.
Riverside is 4-7-3, 3-5-1).
Vanguard 6, San Diego Christian 0
EL CAJON — Amanda Couch had two goals and one assist to pace the visiting Lions in the Golden State Athletic Conference contest Tuesday.
Gabriela Valles had a goal and an assist, while Lindsey Holman-Kelly and Annamarie Tedeschi added goals for the winners (12-3-1, 4-3-1 in conference).
San Diego Christian is 5-10, 1-7.
Orange Coast 2, Golden West 2
HUNTINGTON BEACH — Emma Pridmore and Jessica Parker scored for the visiting Pirates in the Orange Empire Conference game Tuesday.
Jessica Amaral and Brooke Springer had assists for OCC (10-3-4, 7-2-3 in conference).
Golden West is 6-8-3, 4-5-3.
Vanguard def. Point Loma Nazarene
COSTA MESA — KaUwila had 10 kills for the No. 12-ranked Lions, who lost the Golden State Athletic Conference match, 25-17, 25-19, 25-21, Tuesday.
Lisa Morgan led Vanguard (19-9, 8-5 in conference) with 11 digs.
No. 17-ranked Point Loma Nazarene is 14-7, 6-7.
Las Vegas tournament
BOULDER CITY, Nev. — UC Irvine freshman Brenna Carlson shot a career-best 69 to help the Anteaters move into a tie for second Tuesday on the second day of the three-day event at Boulder Creek Golf Club.
Carlson, who was three-under-par Tuesday, has a two-round total of 141, which is tied for eighth. Her 69 ties Sarah Baek for best round of the season for UCI.
UCI senior Lalita Patipaksiri (143) is tied for 12th and freshman Michelle Yang (144) is tied for 15th to pace UCI, which has a team score of 574, even with Pepperdine and seven shots behind UC Davis, heading into the final 18 holes Wednesday.