British Olympic hero Ben Ainslie overcame controversy and an ugly confrontation with a media boat on Saturday to retain a handy buffer heading into the medal race at the ISAF Sailing World Championships. The three-time Olympic gold medallist and leads the Finn class by eight points with just one race to go, despite being disqualified in Saturday's second race and an earlier heated clash with spectators on a media vessel that was filming the racing. Ainslie was apparently furious after the boat caused a wash that he believed hampered him in the first race of the day, in which he finished second, climbing onto the media boat and confronting some of its passengers. He was then black flag disqualified in the subsequent race, which was the first time in the regatta the veteran had not finished in the top three. However, each sailor's worst result deducted is from their overall score and this allowed him to retain his lead. Ainslie is eight points ahead of countryman Giles Scott, with the top 10 sailors in each class facing off in the medal races on Sunday, which are worth double points. Ainslie will face a hearing after Sunday's medal race over both incidents. Meanwhile, Australian pair Malcolm Page and Mathew Belcher all but secured a gold medal in the men's 470. The local duo have an almost unassailable lead and look near certain to retain their world championship crown. Although they only finished fifth and sixth in their two races on Saturday, having won six of their previous seven, it was enough to extend their buffer over British duo Luke Patience and Stuart Bithell, who had a bad day and were joined in second by Croatia's Sime Fantela and Igor Marenic. Page and Belcher lead by 17 points and the only way they can miss out on the gold is if they finish last in Sunday's medal race and one of the two teams in second wins. Patience and Bithell had been challenging the Australians all week, but finished eight and ninth in the two races on Saturday. It is a different story in the women's Laser Radial, with just 12 points separating the top three teams heading into Sunday's medal race. World number one Marit Bouwmeester of the Netherlands took advantage of a faltering overnight leader in Belgium's Evi van Acker, ranked second in the world, to surge into top spot. Van Acker finished 13th and 19th in the day's two races to trail the Dutchwoman by six points, with American Paige Railey the same margin away in third. Three sailors are still in gold medal contention in women's windsurfing heading into the final day, with Israel's Lee Korzits six points ahead of Spain's Marine Alabau and Poland's Zofia Noceti-Klecpacka two points further back.