TAMPA — Sickles used stifling defense and Cary White rushed for 155 yards and two touchdowns to lead the Gryphons past Leto (2-6, 0-3).
Sickles rushed for 307 yards.
"We were moving some people off the line," Sickles coach Pat O'Brien said. "We wanted to come out and start knocking some people off the ball."
White's 25-yard touchdown run in the first quarter jump-started the Gryphons (6-2, 2-1), who clinched a playoff berth for only the second time in their 13-year history.
Leto star Jeremy Deering had 64 yards rushing in the first half, but was held to 11 in the second half.
As time expired in the second quarter, Andres Vasquez made a season-long 43-yard field goal to put the Gryphons up 17-0 at halftime.
Chris Nahat scored on a 48-yard punt return in the third quarter.
Phil Neary, Times correspondent