The unexpected ACC Coastal showdown was the first of a three-week round-robin that will likely determine the division title. The Tar Heels (7-1, 4-0) face No. 22 Duke next at home with a chance to put a vice grip on the program's first trip to the ACC title game.
North Carolina has won seven straight since a sloppy opening loss to South Carolina and is off to its best start since 1997 under Mack Brown.
For the third straight season, Williams came up huge against Pitt (6-2, 3-1). The senior was 14 for 23 for 270 yards and ran for 52. He has 1,020 total yards in three career victories against the Panthers.
Pitt had its four-game winning streak snapped after moving into the rankings for the first time since 2010 behind new coach Pat Narduzzi. The Panthers had won four one-score games with a grinding, low-risk offense and pressure defense, but they looked outclassed by the best offense in the ACC in the first half, falling behind 20-3.
Pitt got a blocked punt by Quintin Wirigins on North Carolina's first second-half possession to set up Chris Blewitt's 29-yard field goal. Qadree Ollison capped a 75-yard drive by pushing into the end zone from 4 yards out to cut it to 23-13 with 4:10 left in the third quarter.
Williams and Switzer have been all kinds of problems for Pittsburgh since the Panthers joined the ACC three years ago. Two years ago at Heinz Field, Switzer, the West Virginia native, returned two punts for touchdowns in a 34-27 victory for the Tar Heels.
Williams last two games against Pitt: 301 yards rushing, 449 yards passing, six total touchdowns.
So fittingly the two combined on the first touchdown of the night. Williams stayed on his feet after getting nearly yanked to the ground by his facemask and unloaded on deep pass to Switzer, who caught it in stride for a 71-yard touchdown pass that made it 10-3 early in the second quarter.
Williams connected with Mack Hollins on a 32-yard TD pass after a Pitt turnover deep in its own territory to make it 20-3 with 3:19 left in the second quarter.
The Tar Heels strong start has been as much about its defensive improvement under new coordinator and former Auburn coach Gene Chizik as its strong offense. The worst defense in the ACC last season has been among the best this season. The Tar Heels had five sacks against Pitt and got strong games out of cornerbacks M.J. Stewart and Des Lawrence.
Nate Peterman threw for 262 yards for Pittsburgh, including a 6-yard touchdown pass to Scott Orndoff with 46 seconds left to make it 26-19. Blewitt missed the extra point.