Paul Menard landed the top spot on the Monster Energy NASCAR Cup Series leaderboard in Friday morning’s opening practice at Dover International Speedway.Menard wheeled the Wood Brothers Racing No. 21 Ford to a best lap of 159.830 mph on the 1-mile concrete layout.RELATED: Practice 1 results | Full schedule for DoverDefending race winner Jimmie Johnson was second-fastest in the Hendrick Motorsports No. 48 Chevrolet, posting a 159.440-mph lap in the final minute of practice. Kevin Harvick was third-fastest in the Stewart-Haas Racing No. 4 Ford, with series points leader Kyle Busch and Brad Keselowski completing the top five in first preparation for Sunday’s AAA 400 Drive for Autism (2 p.m. ET, FS1, MRN, SiriusXM NASCAR Radio).Defending series champ Martin Truex Jr. claimed the sixth-fastest lap in the Furniture Row Racing No. 78 Toyota.A backlog of cars in opening inspection forced several teams to be late in joining the 50-minute session. Just one team served a 15-minute deduction in opening practice, the Premium Motorsports No. 15 Chevrolet of Ross Chastain.Corey LaJoie’s TriStar Motorsports No. 72 Chevrolet slowed in a trail of smoke off Turn 2, forcing a red flag with roughly five minutes left in the session. The stoppage for clean-up of the fluid prompted series officials to extend practice, going back to green-flag conditions for an extra three minutes.Busch Pole Qualifying for the Monster Energy Series is scheduled Friday at 3:20 p.m. ET (FS1).