Skinner led his 18th consecutive race but saw his streak of top-10 finishes end at 14. The O'Reilly finish was his worst since Homestead when he was 35th following an early accident.
Hornaday became just the second driver in series history to lead 6,000 laps as he headed 90 serials at ORP. His total is 6,064. Hornaday has his eye on Jack Sprague's series record of 6,130 laps led.
Hornaday has finished 23 consecutive races since his last DNF on Aug. 12, 2005 at Nashville.
Hornaday's Power Stroke Diesel 200 victory marked the first time that Kevin Harvick Inc. has won three times in a season. Hornaday won twice in 2006.
The driver's last, three-plus win year came in 1998, his second of two championship seasons when Hornaday won six times.
Crew chief Rick Ren was credited with his 14th victory leaving him two shy of the No. 3 all-time total recorded by Rich Burgess. Burgess won 16 times in 1995-96 with Skinner and Richard Childress Racing.
Fifth-finishing Ken Schrader drove the No. 18 Fastenal Dodge to its first lead lap posting since May's race in Mansfield where he took third - the veteran's best of the season.
Regan Smith was a late-week replacement in the No. 47 Morgan-Dollar Chevrolet and gave the team its first top-10 of the year. For Smith, the eighth-place performance was a career best.
It's unknown if Smith will be in the seat when the series moves to Nashville next month.
Brendan Gaughan doesn't particularly care for short tracks but his 10th-place run at ORP was his second top-10 on a "bull ring" this season. The finish boosted the Las Vegas driver to 14th in the point standings - his best since finishing ninth at Mansfield.
Defending race winner Rick Crawford was scored fourth for his 60th career top-five finish. There now have been seven consecutive different short track winners beginning with Crawford's ORP victory.
It is believed the Power Stroke Diesel 200 marked the first time that two Idaho natives started the same NASCAR national series race. Cross-valley neighbors Scott Lynch of Burley and Brett Thompson of Jerome finished 31st and 33rd, respectively.