Mathieu Jaminet had just jumped the #31 Action Express Racing Cadillac in the pits for the lead at the end of the 18th hour when the #6 Porsche Penske entry was penalised for exceeding the amount of energy allowed during a stint.
Jaminet came into the pits shortly after the end of hour 18 to serve his 10-second stop/go, handing the lead back to the #31 Cadillac now driven by Jack Aitken.
The #6 Porsche and the #31 AXR Cadillac were previously running on different strategies, but two caution periods between hours 15 and 18 put them directly against each other as dawn broke in Florida.
Pipo Derani took the lead in the AXR Caddy at the start of the 15th hour, with his advantage standing at 10s after Kevin Estre handed over the #6 Porsche to Nick Tandy.
Tandy brought Derani’s lead down to 3.4s when the first of the two FCYs were deployed, giving the Porsche ace a sniff off the lead.
Tandy upped the pressure on Derani when the race resumed, but the AXR driver was able to resist his advances and extend his lead yet again.
A second FCY followed soon after, during which Jaminet moved back into the #6 Porsche, and the Cadillac vs Porsche battle resumed shortly after.
Jaminet managed to get within touching distance of Derani as the race went back to green, with Matt Campbell in the #7 Porsche also joining the fight.
Derani managed to do just enough to hold on to the position during this stint, with both him and Jaminet heading for scheduled service at the same time at the end of hour 18.
Porsche managed to move into the lead in the pits while AXR completed a driver change, but celebrations in the Penske camp turned out to be short-lived as Jaminet soon had to return to the pitlane to serve his penalty.
This put Aitken, now at the wheel of #31 Caddy, back in the lead, with Campbell running a close second.
Neel Jani was promoted to third in the #5 Proton Porsche from the #40 Wayne Taylor Acura of Louis Deletraz, as Jaminet rejoined the field in fifth.