Boosted by its first top-10 ranking since October 2007, the Wildcats (3-0) followed up last week's Southeastern Conference win at Florida by physically dominating the FCS Penguins (2-1) in the inaugural meeting.
Kentucky outgained YSU 480-192 on the way to its first shutout since beating Miami (Ohio) 42-0 on Sept. 5, 2009. The Wildcats gave coach Mark Stoops a victory over his hometown school, even though he downplayed its meaning all week.
"I'm glad it's all behind us now and really concentrate and move on to to the next games," said Stoops, who was recognized in a pregame ceremony that included his mother and siblings, including his brother Bob, the former Oklahoma coach.
"But a great, great weekend, great day."
Levis posted his second 300-yard effort in three games, completing 27 of 35 attempts for 377 with sparkling catches by his receivers. He hit Dane Key and Chris Lewis with TD passes of 3 and 2 yards, respectively, and rushed for a 1-yard TD early in the second quarter. That run jump-started the Wildcats after a scoreless opening period in which promising drives stalled and Youngstown's Troy Jakubec intercepted Levis at the 3.
Tayvion Robinson's 15-yard catch-and-run across the middle and attempted hurdle over a defender helped set up Levis' TD on third down. Kentucky scored on four of its next five possessions, a stretch split up by a fumble on a day it committed three turnovers with two interceptions by Levis.
"One of those games where we did good things in certain phases and other things continue to creep up and are aggravating," Stoops added. "No panic button, just keep working."
Key caught six passes for 90 yards, while Smoke rushed 18 times for 66 yards including a 7-yard TD.
Youngstown State seemed poised to break the shutout with Demeatric Crenshaw's 64-yard screen pass to Jaleel McLaughlin to the Kentucky 5. That quest ended two plays later when Carrington Valentine tipped Crenshaw's end-zone pass intended for ex-Kentucky player Bryce Oliver and came down with the football.
Kentucky's top-10 status remains safe.
Youngstown State: The Penguins weren't bowed by the Wildcats as they sacked Levis four times and held them to a fourth-quarter field goal after they got inside the 5. But they crossed into Kentucky territory just three times with Crenshaw's interception quashing their best scoring chance.
Kentucky: Pass protection remains a concern after yielding more sacks and allowing the Penguins to record 10 tackles for loss. But the Wildcats regrouped quickly enough to score almost at will in the middle two quarters for a cushion they didn't relinquish. Valentine came up big as well for their fierce defense, breaking a up fourth-down pass in third quarter before his interception preserved the shutout.
Youngstown State visits North Dakota State on Oct. 1 to open Missouri Valley Conference play.
Kentucky hosts Northern Illinois on Saturday night before resuming SEC play.