With space at the top of the mountain tight and riders only being allowed down in cable cars, the day's stage was split up into three different groups. From the first batch of riders it was Thibault Guernalec (Team Arkéa Samsic) who laid down a benchmark for the rest to follow with his time of 48:35 being 1:41 better than his nearest rival, Stephen Williams of Israel - Premier Tech.
When the second batch of riders made their time-trial efforts, numerous riders improved upon the time of Guernalec including some of the stars of the 2023 Giro d'Italia including Ben Healy, Michael Matthews and Thomas Champion.
21-year-old American rider, Matthew Riccitello however, absolutely ripped those times apart. Clocking a time of 46:19 he moved into the hotseat.
When the third batch of riders took to the course, the main GC riders and as such theoretically the best climbers, Jay Vine was the first rider to beat the time over Riccitello by just three seconds.
Vine's teammate Brandon McNulty then went even better. The American posting a brilliant time of 45:30.
Sepp Kuss ensured his fellow American couldn't get too comfortable in the hotseat though, with the Jumbo-Visma super-domestique edging quicker by just two seconds with his time of 45:28.
With each of Almeida, Roglic and Thomas safely through the bike change it was all up to this final, brutal ascent of the Monte Lussari.
At the first time check, Roglic was the quickest but Thomas, just two seconds slower was still in the best position overall.
Thibaut Pinot then went 6 seconds quicker than Kuss, in what must go down as one of the rides of his career which is set to come to an end at the conclusion of this season.
At the second intermediate check, Thomas's deficit had grown to 16 seconds.
Then nightmare struck for Roglic as he got had a mechanical at the worst possible time. Riding straight through a pothole the Slovenian saw his chain drop out.
Both Caruso and Almeida improved on Pinot's time before Roglic, mechanical and all moved into the lead of the stage by a massive 42 seconds.
Then the clock began to tick back to
Geraint Thomas. At the last intermediate check, Thomas was 29 seconds down and the Giro was fading away from the Welshman.