Part-time off-spinner Virender Sehwag picked three key wickets to thwart Australia's grim fightback on the third day of the third Test here on Friday. Sehwag, 30, denied centuries to captain Ricky Ponting (87) and Matthew Hayden (83) before dismissing Michael Hussey (53) as the tourists finished the day on 338 for four in reply to India's imposing 613 for seven declared.