Leopold König slipped one place to sixth overall after a spirited ride on a gruelling 16th stage at the Giro d'Italia.

The Czech star dug deep over 174 kilometres of relentless climbing to finish ninth on the stage in Aprica, on a day which saw the peloton strewn across a brutal parcours.

The feared climb of the Passo del Mortirolo saw the overall contenders forced to fend for themselves on the steep slopes, with König eventually crossing the line three minutes and 19 seconds back on the day's winner.

That honour went to Mikel Landa (Astana), who was forced to leave behind team-mate Fabio Aru on the Mortirolo as the Spaniard, leader Alberto Contador (Tinkoff-Saxo) and Steven Kruijswijk (LottoNL-Jumbo) pushed onwards.

A late dig on the third-category climb to the finish saw Landa take stage honours - his second in succession - by 38 seconds, moving up to second overall in the process.

Contador had to ride through adversity on the stage after a puncture left the maglia rosa isolated and with a 50-second deficit at the foot of the Mortirolo. Riding back to the front he caught and passed Aru, ultimately extending his lead to a commanding 4:02.

König settled into his own rhythm on the extreme gradients, with Team Sky's new leader on the road now sitting sixth overall, 9:21 back on GC, after the toughest stage of the race so far.

The action resumed following the second rest day and it did so without Richie Porte. The Tasmanian headed home after withdrawing from the race due to injuries sustained in a stage 13 crash.

After a tough start the first drama of the stage arrived on the descent following the first of two climbs to Aprica. A puncture for Contador and numerous splits in the bunch saw an intense chase out on the road as the imposing Mortirolo loomed in the distance.

With Katusha and then Astana combining to up the pace, Vasil Kiryienka and König were able to be dragged along, while Tinkoff-Saxo burned through riders to chase back on, with Sebastian Henao and Mikel Nieve sitting in that group.

It was Nieve who was the next Team Sky rider home on the stage in 18th place on his birthday, a result that elevated him three places on the GC to 16th with five stages to go. Elia Viviani also made it through the stage to retain the red points jersey.

"It was a tough day," said Sports Director Kurt Asle Arvesen. "At one point it was down to six degrees. Then it was up to 17 degrees. It would rain, then it was dry. We had slippy roads, steep descents and steep climbs. We had everything here today - except flat!

"It was full on from the start so it was a tough day for everyone. Leo did well and paced himself. He did a good job and that was the best way to ride it. Okay he lost a place on GC but we still have two good climbing stages to go. He's looking forward to them and then we'll see where we are.

"Tomorrow it's a big day for Elia. It's a sprint stage and there are a lot of points to grab, both on the road and also at the finish."