Pogacar's epic Giro win leaves cycling world gasping

Tadej Pogacar keeps taking cycling to new heights, as an unreal fourth stage win at the Giro d'Italia left his rivals, including Aussie Ben O'Connor, gasping.

Ben O'Connor has been left gasping as he battled to keep his podium hopes thriving at the Giro d'Italia while three minutes up ahead in the mountainous distance, Tadej Pogacar was taking everyone's breath away with one of the grand tour's truly grand rides.

The amazing Slovenian Pogacar simply rode away from the field to Livigno for a fourth victory of this Giro on Sunday, making the toughest stage of the whole event, with 5400 metres of climbing, seem just like child's play as he effectively sealed overall victory with a week still to go.

Blasting away to victory by almost half-a-minute from former Giro winner Nairo Quintana while his main rivals were another two-and-a-half minutes further back, Pogacar now leads the race by a massive six minutes and 41 seconds from Geraint Thomas after this unforgettable 15th stage.

While Pogacar was flourishing with his final 14km attack, Perth's O'Connor was left having to hold on grimly with the rest of the scattered pursuers on the steep slopes of the Mottolino climb, desperately trying to ensure his hopes of making the podium weren't damaged too badly.

O'Connor, who traipsed home eighth, did well to lose only eight seconds to Thomas and Dani Martinez, the pair with whom he's now effectively battling for second place.

The Decathlon AG2R La Mondiale rider O'Connor remains fourth in the GC, 47 seconds behind Colombian Martinez and 1:02 adrift of Welshman Thomas.

On the 222 km ride from Manerba del Garda, Pogacar decided to hit the chase button on the penultimate climb of the Passo di Foscagno, immediately burying his main rivals and going on to ruthlessly chase down Colombian Quintana with less than two kilometres left.

Pogacar's advantage is now the biggest for a leader at this stage of the race since 1954, and he looks unstoppable in his bid for the first leg of his planned assault on a Giro-Tour de France double.

"Today was one of the best days for me... it was a really nice stage, really good route with nice climbs. The team did a good job. We had this stage in mind since December," Pogacar said.

"I'm super happy that we kept it under control. It was a really strong breakaway but I gave it all in the last 10, 15 km. I'm super happy I could win a Queen Stage in Livigno, one of my favourite places in Italy.

"I used to watch Quintana and (Chris) Froome attacking each other but always too close to the finish. I was always angry that he (Quintana) wouldn't attack from distance but today he did a good job."