Smith finished with 165 yards on five receptions and also scored a rushing touchdown for the Knights, who improved to 4-0 for the first time since 1988, when UCF was still in Division II.
Milton completed 16 of 19 passes for 374 yards but didn't get a chance for more in the fourth quarter. Lightning and heavy rain moved into area, and the game was stopped with four seconds left in the third quarter and Central Florida leading 51-23.
Officials waited an hour before calling the game.
UCF's season has been severely hampered by weather. Three of the Knights' games had to be cancelled by the hurricanes that impacted the Sunshine State in the last two months. But it hasn't stopped Central Florida from putting up big numbers under second-year coach Scott Frost.
The Knights (4-0, 2-0 AAC) racked up 515 yards of offense in just three quarters.
Cincinnati quarterback Hayden Moore rans for two touchdowns and threw for one to lead the Bearcats (2-4, 0-2), who lost their third straight game.
Moore completed 23 of 40 passes for 278 yards and also led the Bearcats with 75 yards rushing.
Milton completed 10 of 12 passes for 282 yards and four touchdowns in a dominating first half filled with big plays.
The Knights scored touchdowns on the first three possessions. Milton threw a 54-yard touchdown pass to Dredrick Snelson and followed it with a 79-yard completion to Smith to put the Knights up 14-0 five minutes into the game.
Moore tried to keep the Bearcats in the game, more with his legs than his arm. The junior quarterback had two touchdown runs in the first half, including a 16-yard scamper down the sideline that trimmed UCF's lead to 30-13 with 3:57 left in the second quarter.
Milton hooked up with Smith again for a 41-yard touchdown and the Knights went into halftime with a commanding 37-16 lead.
The Knights possessed the ball for just over 10 minutes in the first half, yet racked up 385 total yards.
NOTES: Cincinnati DE Mark Wilson sacked UCF QB McKenzie Milton in the second quarter. It was the first sack Central Florida allowed all season. ... Central Florida entered the game as one of only three teams to be ranked in top 10 in scoring offense and scoring defense. The others are No. 1 Alabama and No. 6 Washington. ... Central Florida coach Scott Frost and Cincinnati coach Luke Fickell squared off against each other in the 2015 College Football Playoff. Frost was the offensive coordinator at Oregon and Fickell was co-defensive coordinator for Ohio State. The Buckeyes defeated the Ducks 42-20. ... Central Florida returns home to host East Carolina next week. Cincinnati travels to No. 18 South Florida.