Klaus Graf set the quickest lap in Sunday morning's warm-up for Mobil 1 presents the Grand Prix of Mosport in Muscle Milk Racing's Lola-Aston Martin coupe. The overall polesitter for today's fourth round of the American Le Mans Series presented by Tequila Patrón turned a lap of 1:10.535 in the car that he will share with Lucas Luhr.

The session was red-flagged midway through after Team Panoz's Edward Sandstrom went off hard into the Turn 3 tire wall at Mosport International Raceway. The impact tore the front-left bodywork away from the Panoz Abruzzi "Spirit of Le Mans."

Chris Dyson was second in LMP1 in the warmup for Dyson Racing at 1:13.872. CORE autosport's Gunnar Jeannette was the quickest LMP Challenge car and second overall at 1:13.713.

Johannes van Overbeek set the pace in GT for Extreme Speed Motorsports. He set a lap of 1:18.550 in the Ferrari F458 Italia that he will drive with Scott Sharp. Van Overbeek was 0.156 seconds quicker than Flying Lizard Motorsports' Jörg Bergmeister and his Porsche 911 GT3 RSR. The top nine cars were within 0.649sec.

TRG's Dion von Moltke went quickest in GT Challenge – 1:24.113 in the Porsche 911 GT3 Cup he will drive with Marc Bunting. The class winner at Lime Rock Park two weeks ago went 0.109sec quicker than class pole-winner Damien Faulkner in the Black Swan Racing Porsche.

Today's race begins at 3:05 p.m. ET with ESPN2 airing the race at 10 p.m. ET.