Australian criterium champion Kaden Groves has been denied a second stage win in the Tour of Slovakia but it took a long study of the photo finish before it was ruled that he'd missed out on victory by the narrowest of margins.

The 22-year-old, who had won the prologue that kicked off the five-day race, delivered a late charge in Saturday's penultimate stage which looked as if it might be enough to see him prevail in a neck-and-neck finish with Kristoffer Halvorsen in Povazska Bystrica.

Race commissaires had to study the photo finish extensively, as the pair waited anxiously, before they ruled that the Norwegian had edged the verdict.

Third place went to Slovakia's national cycling hero Peter Sagan, the Bora-Hansgrohe superstar, whose four bonus seconds were enough to push him into the overall race lead on his home tour just two seconds clear of Colombian Alvaro Hodeg.

Groves was delighted to have bounced back strongly after a couple of days of disappointments which had seen him suffer a dropped chain on the first stage and a crash with 15km left of Friday's second stage.

"We took control and everyone did a great job of delivering me," Groves said of his BikeExchange sprint train on the Australian team's website.

"I got squeezed with about 200 metres to go which cost me a few metres, but thankfully I had good legs and could close the gap to the guys in front. The legs are good, and I showed my speed today.

"It was an awesome, all-round team performance despite the result. Tomorrow is another opportunity, on paper another sprint, so all in for that."

BikeExchange sports director Gene Bates called the day "bittersweet" as Groves had come so close to winning.

"We have one more chance tomorrow and hopefully we can come out on the better side with first place, but hats off to Halvorsen today," he said.