Olson recorded his highest point total of the season by making 8 of 14 shots from the field and 3 of 5 free throws. He converted five 3-point shots while counting five steals, two rebounds and two assists.
Mueller tallied his career-high scoring mark by making 7 of 10 shots from the field and 4 of 8 tosses from the free-throw line. He made a pair of 3-point shots while totaling seven rebounds and four assists.
In addition to the efforts of Olson and Mueller, UW-Oshkosh (5-5) received six points, four rebounds and four assists from Andre Wallace.
Calvin College, which captured NCAA Division III titles in 1992 and 2000, had four double-figure scorers. Jordan Brink led the Knights with 21 points and six rebounds, while Brad Visser added 13 points and Connor Vander Brug 11.
UW-Oshkosh took a quick 6-0 lead on a pair of 3-point baskets from Olson. Calvin College (6-4) answered with seven straight points of its own to take a 7-6 advantage at the 13:35 mark of the opening period.
The Titans regained the lead and built a 20-16 advantage before the Knights went on a 13-4 run to go in front, 29-24, with 1:49 left before the break. An Olson layup with 32 seconds remaining cut UW-Oshkosh's deficit to 31-29 at intermission.
UW-Oshkosh erased its halftime deficit and took a 36-33 lead with 16:39 left to play. Calvin College then went ahead for good at 37-36 and proceeded to score eight of the next nine points to take a 45-37 lead with 12:56 remaining.
The Titans got as close as 53-49 with 7:13 left, but the Knights ended the UW-Oshkosh threat with 10 straight points to take a 63-49 lead with 4:41 remaining.
Calvin College maintained a lead of nine-plus points for the final 1:40 of play by draining all eight of its free throws. The Knights ended the contest shooting a perfect 12-for-12 from the charity stripe.
UW-Oshkosh posted shooting marks of 40 percent (20-50) from the field, 32.1 percent (9-28) from 3-point range and 51.9 percent (14-27) from the free-throw line. The Titans committed 11 turnovers.
Calvin College shot 52.8 percent (28-53) from the field, including 38.9 (7-18) behind the 3-point arc. The Knights committed 17 turnovers while collecting 38 of the game's 61 rebounds.
UW-Oshkosh is off until it hosts Carthage College on Dec. 31 in Kolf Sports Center.