The third seed easily won the first set after breaking a wary Lehecka early on, but the 21-year-old, who has had a breakout tournament, pushed back hard after that. Stefanos Tsitsipas defeated the rising Czech Jiri Lehecka on Tuesday to go to the Australian Open semi-finals for a record-tying fourth time.The third seed easily won the first set after breaking a wary Lehecka early on, but the 21-year-old, who has had a breakout tournament, pushed back hard after that.Prior to travelling to Melbourne, Lehecka, who had never won a Grand Slam match, utilised his strong baseline game to keep up with Tsitsipas in the second set. However, the Greek upped his game to easily win the tiebreak.At 3-3 in the third set, Tsitsipas had to save three straight break points from Lehecka as she attempted to prolong the Rod Laver Arena match.When Lehecka served at 4-5, the 24-year-old pounced, gaining match point with a devastating backhand pass and winning the match when his opponent missed a backhand.Tsitsipas will compete against Karen Khachanov of Russia in the semifinals.