The Bruins, seeded No. 1 in the West Region, will face Xavier Saturday with a trip to the Final Four on the line.
UCLA held Western Kentucky to 19 percent shooting from the floor in the first half and owned a 21-point lead at intermission. The Hilltoppers, however, charged back to within 63-59 on two free throws by Courtney Lee with 5:39 remaining, before UCLA promptly ran off seven straight points.
Love's tip-in with 3:46 to play gave the Bruins a 70-59 cushion and Western Kentucky came no closer than six points the rest of the way.
James Keefe added 18 for the Bruins (34-3) and Josh Shipp had 14.
Tyrone Brazelton led Western Kentucky (29-7), the 12th seed in the region, with 31.
Duggar sisters unveil Christian dating rules in new book
Astronomers offer more expansive view of universe