UMKC used two 10-2 runs in the opening half to help build a 33-24 halftime lead and then nursed its advantage throughout the final 20 minutes. The Kangaroos last beat a power conference team in December 2003 (Kansas State) and haven't finished above .500 in a season since 2004-05.
The Tigers returned just 22 percent of their scoring from a 2013-2014 season that ended in March with a second-round loss in the NIT. Four freshmen received significant playing time Friday for first-year coach Kim Anderson, who guided Central Missouri to a Division II title earlier this year.
Harrison, the reigning WAC Freshman of the Year, averaged 17.2 points per game last season and single-handedly kept UMKC in the lead at times against the Tigers, scoring seven consecutive points midway through the second half.
After an authoritative, two-handed dunk by Gill-Caesar with 4:54 left narrowed Missouri's deficit to 57-53, Harrison answered with a layup on the other end to start a 4-0 UMKC run.
The Tigers would get no closer.
Missouri led for just 34 seconds, grabbing a 3-2 advantage on a free throw by Ryan Rosburg 3:37 into the game. The team trailed by 11 in the first half against Missouri-St. Louis in its second exhibition game on Nov. 8, and Anderson said afterward the deficit would be beneficial to the Tigers.
But there would be no comeback this time.
Missouri-Kansas City: The upset provided the signature win for second-year coach Kareem Richardson, who helped Louisville win the national championship in 2013 as an assistant for Rick Pitino. UMKC also received a big boost of confidence after being picked to finish fifth in the preseason WAC media poll.
Missouri: A scattering of boos rained down at the final buzzer from an announced attendance of 7,014. . Jakeenan Gant sat out after the school issued a release shortly before tip-off saying the freshman would be ''withheld from competition as a result of a review regarding his eligibility.''
Missouri-Kansas City plays at Kansas State on Monday.
Missouri hosts Valparaiso on Sunday.