Quintana leads Tirreno into final day

Australia's Rohan Dennis fell to third in the overall standings as Fernando Gaviria took the penultimate stage of the Tirreno-Adriatico.

Fernando Gaviria has won the sixth stage of the Tirreno-Adriatico cycling race by half a bike wheel. (AAP)

Fernando Gaviria won the sixth stage of the Tirreno-Adriatico cycling race and Nairo Quintana retained the overall lead heading into the final leg.

Gaviria, who rides for Quick Step, held off world champion Peter Sagan in a bunch sprint at the end of the 168km route from Ascoli Piceno to Civitanova Marche to win by half a bike wheel. Jasper Stuyven was third.

"In stage three I crashed and the legs weren't excellent, but now I'm going well," Gaviria said. "The climb before the finish made the race a little Milan-San Remo today. It's always a nice duel with Peter Sagan but also a fight with the other riders."

Quintana remained 50 seconds ahead of Thibaut Pinot, who moved into second, and 1 minute, 6 seconds ahead of Australia's Rohan Dennis.

The breakaway was halted for three minutes near the halfway point after the peloton was held up at a train crossing.

Tuesday's final stage is a 10km individual time trial around San Benedetto del Tronto.