A heavy crash for LMP2 runner Nyck de Vries caused a safety car that impacted the Le Mans 24 Hours GTE battle, but didn't disrupt the Toyotas' overall lead fight.
LMP1 - Kobayashi leads from Alonso
The gap between Toyota's pair of TS050 HYBRIDs remained stable with three hours of the Le Mans 24 Hours to go.
Kamui Kobayashi started hour 21 with an advantage that was the best part of two minutes over Sebastien Buemi, and added to that both while Buemi remained in the #8 and after the Swiss driver had handed over to double Formula 1 world champion Fernando Alonso.
The gap between the two stayed in the 2m-2m10-second range either side of a lengthy safety-car period, which was caused by the Racing Team Nederland Dallara of Nyck de Vries going off at the kink before Indianapolis.
The #7 car ended the hour having completed 333 laps, after which it was 2m06.348s clear of Alonso, who was due to stop near the beginning of the 22nd hour.
Mikhail Aleshin remained a lonely third in the #11 SMP Racing BR Engineering-AER BR1, five laps down on the leading Toyotas but three clear of the car's only remaining threat for the final podium position - the #1 Rebellion of Neel Jani.
Thomas Laurent replaced Nathanael Berthon in Rebellion's #3 R-13, and returned to the top five overall in hour 21.
LMP2 - Signatech-Alpine still one lap clear
Nicolas Lapierre handed over the LMP2-leading Signatech-Alpine to Andre Negrao shortly before the hour mark, without losing its one-lap advantage over Stephane Richelmi's #38 Jackie Chan DC Racing ORECA.
Unable to make much of an impression on the leader, Richelmi instead turned his attention to building a buffer over Francois Perrodo's #28 TDS Racing ORECA in third.
Even after being held at the end of the pitlane after pitting under the safety car brought out for de Vries's accident, Richelmi's advantage was over 90s as Bronze-graded gentleman driver Perrodo approached the end of his final double stint, with Matthieu Vaxiviere due to take the car over shortly after the hour.
Three laps behind the leader, Filipe Albuquerque had cycled ahead of Romain Dumas in the ongoing battle for fourth between the #22 United Autosports Ligier and #30 Duquiene Engineering ORECA, while Paul Lafargue held a two-minute advantage for IDEC Sport over Jean-Eric Vergne's recovering G-Drive Racing ORECA - which was also due a stop after the hour.
GTE - Corvette crash boosts Ferrari
AF Corse stepped towards a Le Mans GTE Pro class victory for Ferrari after Corvette's Jan Magnussen suffered a crash at the Porsche Curves that forced it into the garage for repairs.
Antonio Garcia began the hour behind the wheel of the #63 Corvette and held a six-second advantage over Calado's #51 Ferrari.
But Garcia made a pitstop under the safety car to hand over to Magnussen, who was then held at the end of the pitlane for a significant period of time.
While the gap became an artificial three-minute one under safety car conditions, following the restart Magnussen suffered his spin and made contact with the wall.
He instantly pitted the Corvette and was wheeled into the garage as the team repaired the left-front corner of the car.
Magnussen returned to the track after a six-minute delay eighth in class and it meant Calado's lead grew to 1m30s at the close of the hour.
Magnussen's crash lifted the #91 Porsche of Richard Lietz into second, as Lietz held off a stern challenge from the fellow Porsche of Nick Tandy at the Dunlop Chicane on the restart.
Tandy also earned a 10s stop-and-hold penalty for crossing the white line on the pit exit at his last pitstop.
The 2015 overall Le Mans winner was third at the close of the hour, ahead of three Fords - Dirk Muller leading Andy Priaulx and Richard Westbrook.
Despite an off at the restart, Ben Keating continued to lead GTE Am in his privateer Ford GT by just under three minutes over the Team Project 1 Porsche.