Franco Grilla kicked a 34-yard field goal as time expired Saturday to give Central Florida a 20-17 victory over previously unbeaten Youngstown State in the first round of the NCAA Division I-AA playoffs. Central Florida (9-3), a I-AA independent in its first year in the division after moving up from Division II, meets William & Mary next Saturday in a quarterfinal game in Orlando. Grilla's kick ended a 10-play, 71-yard drive. A 31-yard pass from quarterback Ron Johnson _ a graduate of Northside Christian School in St. Petersburg _ to Sean Beckton gave Central Florida a first down at the Youngstown State 37. On the next play, Johnson found John Osborne for a 14-yard completion that moved the Knights to the Penguins' 23. Three running plays moved the ball to the 17, setting up Grilla's kick. "I looked down at Ron (Johnson, the holder)," said Grilla, "and he just told me to believe in the Lord, and I did." Central Florida head coach Gene McDowell credited his defense, which had sacks to kill Youngstown State's final two drives, with the victory. "If we didn't get those sacks," McDowell said, "there's no question they would have scored." The Knights' Mark Giacone gained 191 yards on 21 carries to break his own single-game school record of 177 yards set in October 1987 against West Georgia. Giacone also became the first Central Florida player to rush for more than 1,000 yards in a season. He has 1,137 yards. "I never thought I had that much yardage," said Giacone. "But the guys up front did a great job of blocking today. The key was that even though we led at halftime (17-6) we never got content." Johnson completed 8-of-11 passes for 106 yards. He threw no interceptions. Quarterback Ray Isaac marched the Penguins (11-1) 59 yards in the fourth quarter, completing all four of his passes, to set up a 41-yard field goal by Jeff Wilkins that tied the game at 17 with 5:17 to play. _ Information from the Youngstown Vindicator was used in this report.