Nairo Quintana claimed the overall lead in the Giro d'Italia on Friday after Tom Dumoulin lost ground in the final ascent of an eventful 19th stage won by Spain's Mikel Landa, meaning the race is likely to go right down to the wire.
Quintana's Movistar team attacked 135km from the finish when Dumoulin (Team Sunweb) was at the back of the peloton, possibly because nature had called and after clawing his way back, the Dutchman found he could not follow in the 15.5-km climb up to Piancavallo.
Frenchman Thibaut Pinot was the overall contender who gained most after he dropped Quintana and Italian Vincenzo Nibali (Bahrain-Merida) with about six kilometres left.
Quintana now leads second-placed Dumoulin by 38 seconds, third-placed Nibali by 43 and Pinot (FDJ) by 53.
Saturday's penultimate stage will feature two big climbs that could favour Nibali, Quintana and Pinot, while Sunday's final time trial, a 29.3-km effort, is expected to go Dumoulin's way.
Dumoulin, who exchanged angry words with Nibali on Thursday saying he hoped he and Quintana would lose their places on the podium after they refused to help him out when Pinot had attacked, stayed clear of controversy this time.
"I had bad legs from the start. I made a mistake at the start and in the finale I tried to limit my losses and did that well," he said.
"The team saved me a couple of times otherwise it would have been a much worse day. Just bad legs today. With good legs it would have been possible to stay in the lead but they weren't there."
Nibali had replied on Thursday saying the race was not over and "anything could happen" -- and it did as the defending champion, Pinot and Quintana pulled away when Dumoulin was at the back of the pack.
Quintana said: "It is complicated. Mental strength will make the difference, strategy, too. Tomorrow is another hard day and then there is the time trial. Anyone (of the top four) can win it."
On freshness, however, Pinot has had the edge over his rivals in the past couple of days, Nibali and Quintana being unable to follow when he attacked on Friday.
Further up the road, Landa soloed to the stage victory to give Team Sky something to cheer about after their leader Geraint Thomas was forced to abandon early in the race after a crash. The win was all the sweeter for Landa after he had come a close second in two previous stages of this year's Giro.
(Reporting by Julien Pretot; Editing by Hugh Lawson)