Defending champion Vincenzo Nibali says he has no gripe with Giro d'Italia rival Nairo Quintana, but warned the Colombian sparks could fly when they race to the first summit finish on Mount Etna Tuesday. After Monday's rest day, the 100th edition of the race resumes Tuesday with a 181km fourth stage from Cefalu in the north of Sicily to the summit of Europe's highest active volcano. Fernando Gaviria, another Colombian, who rides for Quick Step, will start in the pink jersey after he took the race lead from fellow sprinter Andre Greipel by winning stage three to Cagliari, Sardinia, on Sunday. But after three days of seeing the fast men of the peloton sprinting for glory, fans get a chance to tune in for some early-race salvoes in the definitive battle for the pink jersey. It is the first summit finish of the race and Nibali, the winner in 2013 and 2016, expects 2014 champion Quintana to put the hammer down. "It's inevitable that something happens, because Etna is a real challenge," Nibali said Sunday when asked about the threat from Quintana. Nibali, also the 2015 Tour de France champion, refuted reports in Gazzetta dello Sport of tension between him and climbing specialist Quintana, who rides for Movistar. "No, not at all," Nibali said. But Nibali, born and raised in the Sicilian town of Messina, said he isn't racing for charity. "He races for one team and I race for a rival team, so it's only normal we're enemies," he said. "We don't acknowledge each other that often, because we're both very concentrated and have to pay attention on the road. But we're both here trying to win it." Only four stages into the race's 100th edition, the ride to Mount Etna is certain to see Gaviria, a sprint specialist who excels on the flat, hand the coveted pink jersey over to a new race leader. After a first 55km over undulating terrain, the peloton will tackle the 32.8km climb to the summit of Portella Femmina Morta. Rather ominously, it translates to 'Dead Woman's Door'. Thankfully, it's average gradient is a manageable 4.5% on average. After a long, winding descent, a more formidable, 17.9km ascent to Etna, where the steepest sections reach 12%, provide a far tougher challenge. "It won't be decisive, but the stage to Etna is important because it will give me an indication of my form and an indication of who the real GC (general classification) contenders could be for the final week," said Quintana. As well as Nibali and Quintana, fellow GC contenders like Steven Kruijswijk (LNL), Spaniard Mikel Landa (Sky) and Tom Dumoulin (Trek) are expected to be at the front of the peloton. A prestigious stage win is at stake, although the responsibility of controlling the race would then fall to the team of the new pink jersey holder — demanding precious energy that could prove useful for more decisive stages in the third and final week. Yet, with stage five finishing in his home town of Messina, Nibali has extra incentive to claim the 'maglia rosa' on Tuesday. "I can't wait for the stage to Messina, it's my home town," he said. Authorities ordered to pay Heras compensation Spanish authorities must pay former cyclist Roberto Heras 725,000 euros ($794,000) in compensation for an overturned positive doping test after Spain's Supreme Court rejected their appeal, a court filing said on Monday. Heras tested positive for banned substance EPO in the 2005 Tour of Spain and was banned for two years by Spain's Royal Cycling Federation. He was also stripped of the title, which would have been a record-breaking fourth Tour of Spain win. The positive test was overturned in 2011 by a civil court in Castile and Leon, which ruled that irregularities had taken place in the analysis of blood samples in the investigation. The Supreme Court upheld that decision in 2012 and ordered Heras be reinstated as the 2005 Tour of Spain winner. Heras, a former teammate of disgraced cyclist Lance Armstrong with the US Postal Service team between 2001 and 2003 and Tour of Spain champion in 2000, 2003, 2004 and 2005, sued the Spanish state for over 1 million euros in damages in 2013. Spain's National Court ruled in his favor but reduced the compensation to 725,000 euros, which it said was half the salary he received in his last year as a cyclist. The Supreme Court said in a statement it rejected the Spanish state's appeal because the overturned sanction was the direct cause of Heras losing commercial and professional contracts. Neither Heras nor Spain's cycling federation responded to requests to comment on the ruling. — Agencies