CERVINIA, Italy (AP) -- Alberto Contador had 38 seconds sliced off his overall lead in the 19th stage of the Giro d'Italia on Friday, although the Spaniard remained well on course for the title.
Italian rival Fabio Aru won the mountain stage with a late breakaway and moved back into second place overall, 4 minutes, 37 seconds behind Contador.
Aru's Astana teammate Mikel Landa dropped to third overall, 5:15 back, entering Saturday's final mountain stage before Sunday's flat finish in Milan.
Aru required nearly 6 1/2 hours over the 236-kilometer (147-mile) leg from Gravellona Toce to Cervinia, which included three major climbs, including an uphill finish.
Ryder Hesjedal, the 2012 winner from Canada, finished second, 28 seconds behind, and Rigoberto Uran, the Colombian who finished second the last two years, crossed third, 1:10 back.
Contador and Landa were in a group of riders who finished 1:18 behind.
Contador showed little interest in chasing Aru, choosing to follow Landa instead.
"I was marking Landa, my biggest rival," Contador said. "Aru was the strongest today."
Contador may have also been saving his energy for Saturday's penultimate stage, a 199-kilometer (124-mile) leg from Saint-Vincent to Sestriere that includes a grueling climb up a dirt road on Colle delle Finestre.
Contador has not won a stage in this year's race.
"I've been working for the pink jersey for five months," Contador said. "Winning a stage is secondary."
Contador is attempting to become the first rider since Marco Pantani in 1998 to win the Giro and Tour de France in the same year.
A two-time Tour champion, Contador won the Giro in 2008 and was also triumphant in Milan in 2011 but was stripped of that title for testing positive in the 2010 Tour.