Samantha Stosur dropped an epic second-set tiebreaker but recovered to beat Maria Kirilenko 6-2, 6-7 (15/17), 6-3 on Sunday to reach the quarter-finals of the US Open. Russia's Kirilenko prevailed in what the WTA said was the longest women's singles tiebreaker at a Grand Slam tournament to knot the fourth-round match at a set apiece.