Brandon McNulty (UAE Team Emirates) upended the battle for the overall of the Itzulia Basque Country after a powerful attack over the top of the final climb of stage 4 saw the American racer capture the overall lead.
In a fraught finale, former leader Primož Roglič (Jumbo-Visma), whose main rival looked certain to be Tadej Pogačar (UAE Team Emirates) lost nearly a minute and has now dropped to 23 seconds overall behind McNulty, with Pogačar dropping from second to fifth overall, at 43 seconds on his teammate.
The major shakeup brooks for a fascinating showdown on Saturday's final Queen stage of the race, culminating in Mount Arrate, a summit finish where Roglič won in the Vuelta a España last autumn.
But for now, McNulty is the new leader of the Itzulia Basque Country, and the odds of his becoming the first American overall winner since Chris Horner back in 2010 have considerably increased.
Having first attacked on the last ascent of the day, McNulty told reporters afterwards that "the plan going into today was for Tadej to go on that in final climb and then I'd try on the small kicks on the descent, but everyone was looking at each other and I went for it myself."
That move was brought back, but then when Esteban Chaves (Mitchelton-Scott) and Pello Bilbao (Bahrain-Merida) attacked and McNulty came across with Jonas Vingegaard (Jumbo-Visma), Emanuel Buchmann (Bora-Hansgrohe) and Ion Izagirre (Astana Pro Team) on the false flats after the summit it proved to be a very different story.
"There was another acceleration which moved away and we rolled it all the way to the line," McNulty said. "We worked hard together, and it was very good for me today, it all worked out very well."
Asked why he thought the rival squads had not chased harder behind, McNulty argued that both UAE and Jumbo-Visma had GC representatives present, which gave his breakaway group more options. Furthermore, by the time Movistar and Ineos began to chase behind it was too late.
A third-place finish in Hondarrabia allowed McNulty to gain a four-second time bonus as well as the 49 seconds the break finally gained on the chase group, and as result, he has leapfrogged over the two Slovenians into first place overall. But if McNulty is the new leader, Vingegaard has moved up into third place in the provisional GC, at 28 seconds, giving the Dutch team another option besides Roglič.
For McNulty, leading such a prestigious WorldTour race represents another big step up in the 23-year-old's promising career, but as he recognised the GC game is far from over. The key Arrate stage is yet to come on Saturday and the bad weather forecast for the weekend will surely render the climbs and descents that day even more difficult.
"The final day is a real showdown, it'll be super hard all day and I hope I have legs for the finale," McNulty said. "But we've got Tadej as well and we'll do our best to defend the jersey."
