The #8 Toyota GR010 Hybrid driven by Brendon Hartley was circulating just over a second clear of the sister #7 entry piloted by Kamui Kobayashi after four hours of racing at the Sebring International Raceway.
The #50 Ferrari 499P that Antonio Fuoco had qualified on pole position led the action early on, but a decision by the Italian manufacturer to bring both its cars to the pits under a safety car in the first hour backfired, dropping them into the middle of the Hypercar pack.
This put Sebastien Buemi in the lead of the race in the #8 Toyota, with Mike Conway running a few seconds back in the sister #7 entry.
Buemi and Conway maintained a gap to each other in the opening stints and it was only after they handed over the cars to Hartley and Kobayashi respectively that the two Toyotas started to battle for position.
However, despite Kobayashi looking strong after taking over the #7 Toyota, Hartley managed to hold his position at the front - even when he had to make two pitstops in rapid succession in the fourth hour, including one to top up on fuel under a full course yellow.
Cadillac provisionally holds the final spot on the podium with Earl Bamber at the wheel of the #2 Chip Ganassi V-Series.R, aided by a charging stint from Alex Lynn in the second hour when he passed both the Porsche 963 LMDhs for third.
However, Lynn partly undid his good work by not respecting the full-course yellow procedure at the end of hour two, picking up a drive-through penalty as a result.
The #50 Ferrari runs in fourth place, with Nicklas Nielsen currently at the wheel after taking over the driving duties from Miguel Molina just before the halfway point of the race.
The car lost ground after picking up two different penalties in the first half of the race, having already dropped down the order with a pitstop under the safety car in the opening hour.
A drive-through penalty was handed to the leading Ferrari when Fuoco passed a GTE car before the safety car period was over in the first hour, while five seconds were added to its pitstop time when the Italian was found to have not followed the correct full-course yellow procedure later in the race.
Andre Lotterer is running fifth after a trouble-free run for the Porsche’s two LMDh cars, the #6 963, with the sister #5 car sitting two places behind after earning a drive-through penalty for a yellow infringement.
The #51 Ferrari lacked pace of its sister entry and was running sixth overall with James Calado at the wheel after a late off for the British driver at the exit of Turn 5.
Peugeot endured a disastrous first half of the race with a number of technical issues consigning both 9X8 LMH cars to behind the wall for prolonged periods.
The #94 entry encountered a gear-shifting issue at the very start of the race, with more mechanical gremlins later on leaving the car shared by Loic Duval, Gustavo Menezes and Nico Muller in the garage.
The #94 Peugeot also had a troubled run on what is the car’s fourth-ever race, with an incident between Mikkel Jensen and the Vanwall of Esteban Guerrieri compounding the misery of the French marque.
Jensen was caught out when Guerrieri slowed down in response to a full-course yellow at the end of hour three, suffering a spin as a result.
The #4 Vanwall picked up a puncture in the process and had to pit immediately the next time by, but Guerrieri was still running ahead of both Peugeots in eighth after an otherwise clean debut outing for the Colin Kolles-run outfit.
Glickenhaus retired from the race after Romain Dumas stopped on track at Turn 17 in the second hour with what appeared to be an electrical issue. His team-mate Ryan Briscoe had previously lost power in the opening hour after a full course yellow period, but he was able to get back to full speed without losing much ground.
United issues hand LMP2 lead to Prema, Ferrari rolls
Jota leads the LMP2 class with the #48 ORECA-Gibson 07 of David Beckmann after the long-time leading #23 United Autosports car retired with mechanical problems.
Oliver Jarvis led the early part of the race after qualifying the car on pole position, with Joshua Pierson carrying on his team-mate’s good work after being put in the driver's seat at the end of the second hour.
But Pierson’s ORECA suddenly crawled to a halt in the fourth hour, ending the #23 crew’s hopes of repeating their Sebring victory from 12 months ago.
Jota leads in class from the #31 WRT of Sean Gelael, with Mirko Bortolotti making it three different teams inside the top three in the #63 Prema car.
Meanwhile Corvette Racing holds the top spot in its first outing in GTE Am, with Silver-rated Nicolas Varrone running 13 seconds clear in the #33 C8.R GTE car.
Corvette was handed the lead of the race when the #85 Iron Dames Porsche 911 RSR-19 of Rahel Frey went wide over the kerbs at the exit of Turn 1, with the impact breaking apart the car's entire rear bodywork.
There was a major crash for Richard Mille driver Luis Perez Companc in the opening hour of the race, with the Argentine’s #83 Ferrari landing upside down after going wide at Turn 1 and into the barriers.
