Tom Dumoulin (Team Sunweb) crossed the stage 6 finish line atop Mount Etna, not feeling dramatically satisfied with his first high-mountain performance, but at least able to say that he was one of the few GC riders to test Chris Froome's climbing form.
Dumoulin was impressed by Froome, who responded well to an acceleration by the Dutchman in the closing kilometres despite looking - according to Dumoulin - to be in trouble at one point.
The Giro d'Italia's defending champion crossed the line in eighth place at 26 seconds behind stage winner Esteban Chaves (Mitchelton-Scott) and stays in second overall at 16 seconds behind new race leader Simon Yates.
"I was good today, but I was definitely not the best, that was Yates," Dumoulin told reporters afterwards.
"Chaves' [performance] was hard to evaluate because he started the climb with a minute's lead. But Yates was outstanding. He was the only one who could put in a major attack and get away. He's going to be a dangerous contender.
"It was a very hard climb, it went up 40 kilometres, with steep parts and then less steep parts. At first, I didn't feel good, in the middle it was better, but I didn't have much left in the tank by the end.
Dumoulin had already taken time on Froome in the opening time trial, but he was clearly determined to make the most of his good form on the climbs, too, rather than play a defensive game until the next time trial.
Indeed, Dumoulin tried to distance Froome near the top of Mount Etna with a surging acceleration. "I looked at him out of the corner of my eye and thought he was in difficulty," Dumoulin explained. "I thought maybe he could get dropped. But instead, he came back up through the group at his own pace."
As for his own climbing performance, which never shone as brightly as he had at Oropa or the Blockhaus last year, but was by no means disastrous, Dumoulin was uncertain.
Asked how he would rate his performance on Mount Etna, Dumoulin said, “Not perfect, not bad," he told reporters as he headed away from the finish.
"I had some legs but not the best. Or maybe," he asked rhetorically, "today was my best day, and I'll start going worse from here on. Really, I don't know yet."
Dumoulin will not have to wait too long, in any case, for the next test of his climbing ability. Saturday's ascent of the Montevergine is not too difficult, but Sunday's brutally long final ascent of the Gran Sasso is another story altogether - and a much harder one.