The gaps remained consistent for the first 20 minutes of the fifth hour in LMP1, with Kobayashi in the #7 Toyota roughly 50 seconds ahead of team-mate Fernando Alonso in the #8 Toyota. Nathanael Berthon in the #3 Rebellion continued to lead the non-hybrids in third, but was being rapidly caught by #11 SMP, with Stoffel Vandoorne at the wheel.
Egor Orudzhev followed in fifth in the #17 SMP, still around 24 seconds behind his team-mate, with Lotterer a further two laps back in sixth. Oliver Webb was ninth overall, behind the two leading LMP2s, a further lap behind Lotterer. Renger van der Zande was still way down the order after the #10 DragonSpeed’s earlier issues, placing in the mid-50s for the whole hour.
However, just over halfway into the hour, Vandoorne finally caught Berthon, with less than a second between the two. As with all racing, catching is much easier than overtaking, and Vandoorne stayed behind, with traffic causing the Belgian to slip back to two seconds behind, and once he pitted, handed the car over to Mikhail Aleshin, meaning the pass would have to wait until later.
Berthon pitted a lap later for full service of tyres, fuel and driver change, handing the car over to Thomas Laurent. Lotterer also pitted his #1 Rebellion just before the full-course yellow, handing over Swiss Neel Jani.
After the full-course yellow, the gaps had come down a bit, with 40 seconds between Kobayashi and Alonso, with the #11 SMP of Aleshin and #17 of Sirotkin managing to leapfrog Laurent during the pitstops. All three were a lap down to the Toyotas, with Sirotkin 10 seconds behind his team-mate and Laurent 30 seconds adrift.
Roman Rusinov holds the lead in LMP2 for the #26 G-Drive Oreca squad, having built a gap over Pierre Thiriet in the #36 Signatech Alpine.
As the race entered its fifth hour, the gap between the duelling leaders in LMP2 extended gradually; after 10 minutes of the hour, the pair were separated by two-and-a-half seconds.
Sure enough, both cars would pit on the same lap once again with almost 20 minutes of the hour in the books. Rusinov took over the leading #26 Oreca from Job Van Uitert. The young Dutchman told Nick Daman on Radio Le Mans: “It was a good fight with Thiriet, and it feels good to be in the lead again, but it’s a long race and we have to keep our feet on the ground.”
Thiriet stayed behind the wheel for another stint. Over the course of this stint, the gap would gradually extend, with Rusinov building a ten second gap over Thiriet.
The battle for third in class was still roughly 40 seconds back from the top two with half of the fifth hour in the book; Gabriel Aubry (#38 Jackie Chan DC Oreca) holding a 28-second advantage over Pastor Maldonado in the #31 DragonSpeed Oreca.
With 10 minutes of the hour left to run, a GTE AM-triggered Full Course Yellow created drama for both cars in the LMP2 top two, as they both needed to pit in spite of the pit lane being effectively closed under FCY conditions.
Both cars took on five seconds of fuel per the ‘emergency services’ regulation, and then pitted for a full service on the next lap, just after the clock ticked over to start the sixth hour.
Meanwhile, the Spirit of Race Ferrari that caused the pause held up the #37 Jackie Chan DC Oreca out of fourth at pit entry, much to the chagrin of driver Ricky Taylor, who came in just as green-flag action resumed.
The race in the fifth hour turned into a four-car battle after Corvette had had its own way for a couple of hours. It would be the #92 Porsche of Laurens Vanthoor who would lead at the end of the hour.
Mike Rockenfeller in the #63 Corvette was caught by the #51 AF Corse Ferrari of Daniel Serra, Earl Bamber in the #93 Porsche and the #92 Porsche of Vanthoor.
Serra in the Ferrari had been the fastest car, but over time the two Porsches were able to ease up to the back of the Corvette, with the four cars being separated by barely 1.6 seconds 20 minutes into the hour.
Recognising the endurance element of the race, the Porsches in particular were looking to save fuel and tyres behind the Corvette and Ferrari, rather than attack for the lead. The slipstream would be well used by the following trio.
Eventually, a race would break out with traffic producing some interesting moments. At 33 minutes into the hour, Serra had enough behind the Corvette and took the Ferrari into the lead of the category – quite an achievement after starting 12th.
That same lap, Bamber took himself out of the reckoning with a pitstop – a little earlier than the rest of the battling group. Rockenfeller in the Corvette would come in 42 minutes through the hour and only take fuel – part of the gang looking to double-stint tyres.
Vanthoor and Serra would come in the pits one lap later, also double-stinting their tyres. This move returned all four to the same strategy, save a few laps.
Vanthoor was able to get out ahead of Serra, with the Porsche pitstop 1.3 seconds faster than Ferrari. The Ferrari had taken on left side tyres, offering more grip at Indianapolis – which could prove key.
After the pitstops, Vanthoor lead from Serra with Rockenfeller in third and Bamber in fourth, ensuring it is a Porsche, Ferrari, Corvette, Porsche battle.
As for the rest of the field, there was a minor moment with the #67 Ford of Andy Priaulx, who came in contact with the Larbre LMP2 machine, but continued without damage.
Dennis Olson in the #94 Porshce was issued a 10-second penalty for track-limits infractions, joining the long list in the GT field to be pinged under that rule, with Tertre Rouge being the primary location for offences.
The lead continued to swap between the #77 Dempsey-Proton Porsche of Christian Reid and the #85 Keating Ford of Felipe Fraga as the two teams went through their pitstop cycles. The Ford would hold the class lead at the end of the hour.
For much of the hour, third was held by Patrick Lindsay in the #56 Project 1 Porsche before his pitstop at the end of the hour. He was in a battle with Wei Lu in the #83 JMW Ferrari; the two separated by less than a second was the closest battle in the class.
The #98 Aston Martin with Paul Della Lana behind the wheel took to the gravel at the Porsche Curves. He was able to extract himself but crawled back to the pits. It seemed as though something had broken on the car, but the team confirmed it was only a precaution. It won’t play much of a role in the race, though, having lost 17 laps with earlier problems.
Nearing the end of the hour, the Porsche Curves caught out the #54 Spirit of Race Ferrari, which rotated many times. Francesco Castellacci beached it and caused a full-course yellow. In the past, this would have been a big crash, now, just beached in the gravel.
Once the car was recovered it returned to the pits for checks – necessary, as it seemed he damaged all four tyres in the spin. Both the Aston Martin and Ferrari would be back out on track by the start of hour six.