The #01 Chip Ganassi Racing with Felix Sabates BMW Riley was holding station at the sharp end of the field as the 2013 Rolex 24 at Daytona entered its last four hours of action.
The #10 VelocityWW Corvette DP was only three seconds back as the hour began, suggesting that it will go down to a straight race between the two cars, currently piloted by Memo Rojas and Ryan Hunter-Reay respectively.
As the hour kicked off, three cars found themselves off the tarmac as the #2 Starworks with Alex Popow Ford Riley and the Audi R8s of #51 APR Motorsport Ltd.UK and #24 Audi Sport Customer Racing/AJR ended up going through the run off areas. Despite the spins, there was no full course caution.
Nearing the halfway stage of the hour and Rojas was stretching out his lead over Hunter-Reay, while Justin Wilson in the #60 Michael Shank Racing Ford Riley battled with Burt Frisselle in the #9 Action Express Racing Corvette DP for the final podium spot.
The 14th full-course caution was thrown with three hours and forty minutes remaining as the #02 Ganassi car of Dario Franchitti found itself stranded in the middle of the circuit, leaving Ganassi only one car left to worry about for the remainder of the race. Pitstops once again shuffled the field under the safety car.
During the caution period, Wayne Taylor, crew chief for the #10 car voiced his doubts on the legitimacy of the #02 car’s retirement, stating he found it “a little strange that the #02 car stops on track just as the #01 car wants to change brakes”, whilst Franchitti stated he feared there was an issue with the gearbox or drive shaft.
The race went green once again with eighteen minutes left of the hour led by the #10, ahead of the #9 and #60 cars, before the #01 retook the lead as the hour drew to a close.
The lead in the GT class was held by #44 Magnus Racing Porsche GT3 at the turn of the hour, followed by the #69 AIM Autosport Team FXDD with Ferrari and then the #24 rounding out the top three.
After the caution period, the #69 car had switched places with the #44 with Jerome Bleekemolen in the #23 Alex Job Racing Porsche GT3 battling with the #24 Audi Sport Customer Racing/AJR Audi R8.
The #16 Napleton Racing Porsche Cayman was closing in on class victory as the race wore on, holding a 5 lap lead with just three hours remaining.
2013 Rolex 24 at Daytona Daytona Prototype standings after 21 hours
1 – #01 Chip Ganassi Racing with Felix Sabates BMW Riley
2 – #10 VelocityWW Corvette DP
3 – #9 Action Express Racing Corvette DP
4 – #60 Michael Shank Racing Ford Riley
5 – #90 Spirit of Daytona Racing Corvette DP
2013 Rolex 24 at Daytona GT standings after 21 hours
1 – #44 Magnus Racing Porsche GT3 Cup
2 – #69 AIM Autosport Team FXDD with Ferrari Ferrari 458
3 – #23 Alex Job Racing Porsche GT3
4 – #52 Audi Sport Customer Racing/APR Motorsport Ltd.UK Audi R8 GRAND-AM
5 – #63 Scuderia Corsa Michelotto Ferrari 458
2013 Rolex 24 at Daytona GX standings after 21 hours
1 – #16 Napleton Racing Porsche Cayman
2 – #22 Bullet Racing Porsche Cayman GX.R
3 – #38 BGB Motorsports Porsche Cayman GX.R