McConkey's 6-yard TD pass to Smith capped an impressive opening drive of the game, but Nick Stemmet and Yorkville's defense limited the Spartans to 28 yards the rest of the half.
Preston Ruud's 51-yard interception return set up Sycamore's go-ahead 5-yard TD run that made it 13-10 with 7:50 left in the third quarter. Yorkville came right back, Beetham's 41-yard pass to Brock Grimaldi leading to Cade Henry's second field goal, from 35 yards out, to tie it 13-13.
"It was a good old fashioned football game, that's the way these games are in this conference," McGuire said. "We expected a defensive battle and that's what it was."
Sycamore, in pulling the win out, overcame a devastating last-minute loss to DeKalb in Week 4.
"We just beat a really good team on their field," Ryan said. "We didn't get what we wanted at the end of regulation, but we kept battling back. I reminded our kids that we're a pretty good team too, and they just had to keep believing, and they did, and we won one in overtime."