Leander Paes has stormed into the quarter-finals of both men's doubles and mixed doubles events at the Australian Open in Melbourne on Tuesday. Paes and his Czech partner Lukas Dlouhy out played the American pair of John Isner and Sam Querrey 6-3, 7-5 in the second round of the men's doubles competition. They will next take on the winners of the match between fifth seeds Lukasz Kubot and Oliver Marach and the unseeded duo of Ivo Karlovic and Dusan Vemic.Leander Paes and his Zimbabwean partner Cara Black beat Uzbek-South African pair of Akgul Amanmuradova and Rik De Voest in straight sets 6-4, 6-2 in the second round of mixed doubles event.Serena and Venus Williams are on track for a sisters semifinal at the Australian Open after fourth round wins. Venus advanced to the quarterfinals for the seventh time by beating Italy's Francesca Schiavone 3-6, 6-2, 6-1 in the opening match. Defending champion Serena had a 6-4, 6-2 win over Australia's Sam Stosur.In men's fourth-round matches, Novak Djokovic beat Poland's Lukasz Kubot 6-1, 6-2, 7-5 to set up a quarterfinal against Jo-Wilfried Tsonga.