Joey Logano was fastest in the first of two Saturday practice sessions at Dover with a lap of 157.494mph.
The No. 22 was one of the first on track for the 50-minute session. He wound up faster than his Team Penske teammate, Brad Keselowski, who ran a single-best lap of 157.453mph.
Martin Truex Jr. was third fastest at 157.048mph. Chase Elliott was fourth at 156.883mph and Aric Almirola rounded out the top five at 156.856mph.
Completing the 10 were Kevin Harvick (156.842mph), polesitter Kyle Larson (156.835mph), Ricky Stenhouse Jr. (156.788mph), Kurt Busch (156.733mph) and William Byron (156.644mph).
There were no incidents in the session.
Defending race winner Jimmie Johnson was 13th in the session at 156.515mph. Fall winner Kyle Busch was 15th fastest at 156.386mph.
Trevor Bayne, Chase Elliott, Gray Gaulding, Kasey Kahne and Derrike Cope all served 15-minute penalties during the session for being late to qualifying inspection.
All 38 cars participated in the session.
UP NEXT: Final practice at 11 a.m. ET.