Walker scored 36 points overall and was the key factor in the Huskies fighting off a rally that saw the Aztecs take the lead with 8 minutes remaining.
Connecticut earned a spot in the regional finals Saturday against No. 5 seed Arizona, which pulled off a shocking 93-77 victory over top-seeded Duke.
The Huskies led by nine at the break, and then saw the Aztecs come back to take a 54-51 lead. Walker made back-to-back baskets to put Connecticut back in front for good, and then hit a key 3-pointer with 6:12 to go that lifted the Huskies in front by six.
Jeremy Lamb added 24 points for the Huskies, the region's third seed, who will take a 29-9 record into Saturday's game. Connecticut has won eight in a row, including five in five days while claiming the Big East Conference Tournament title two weeks ago.
San Diego State (34-3) was led by D.J. Gay with 16 points. Star forward Kawhi Leonard was limited to only 12 points while spending much of the second half in foul trouble.