Porter completed the 6-kilometer course in 21:00. That was 24 seconds faster than the record she set in 2008.
"Sarah had been sick all week or she could probably have run even better," said Western coach Pee Wee Halsell.
In the women's division, Alaska Anchorage edged defending champion Club Northwest, 42 to 49. Victoria was third (53) and Western fourth (88).
Porter, a two-time All-American, has won seven of her last eight regular-season meets and finished among the top 10 in all 14 regular-season events during her four-year career. Earlier this season, she placed third at the Greater Louisville Classic, and last year finished second at the NCAA II national championships.
Alaska Anchorage had three top 10 finishers, led by runner-up Miriam Kipng'eno (21:11) and third-place Ruth Keino (21:14).
Seattle Pacific was led by junior Natty Plunkett’s 24th place finish in 23:11, as the Falcons finished fifth.
St. Martin’s was seventh with 222, while Central Washington was eighth at 231, and Northwest University ninth with 259 points.
Marko Cheseto and Micah Chelimo finished 1-2 to lead nationally ninth-ranked Alaska Anchorage to the men's team title Saturday.
The Western men were second in the 11-team field with 65 points. Alaska Anchorage, which placed five runners among the top 11, had a winning score of 33.
Club Northwest was fourth with 104, while St. Martin’s was seventh with 190 points. Seattle Pacific finished eighth at 207 points, and Central Washington ninth at 225 points.
The Vikings, whose five-year winning streak was snapped, had three runners among the top 10. Defending champion Jordan Welling was third in 31:36, with Bennett Grimes fifth (31:34) and Blake Medhaug eighth (31:45). It was the third consecutive top three finish for Welling in the meet, and the fourth straight top five placing for Grimes.
The Vikings entered the meet ranked No.11 in the men's division and No.8 in the women's division in the United States Track & Field and Cross Country Coaches Association NCAA Division II Top 25 polls. Alaska Anchorage was No.4 in the women's poll and No.9 in the men's rating.
Western, Central, Seattle Pacific, and St. Martin’s next compete in the GNAC Championships in two weeks in Yakima, hosted by the Wildcats.
Complete results from the Viking Invitational cross country meet are available here.
NOTE: The sports information offices of Seattle Pacific and Western Washington University contributed to this report.