Fifth seed Stefanos Tsitsipas defeated world No. 2 Daniil Medvedev in straight sets, 6-3, 7-6 (7-3), 7-5, to enter semi-finals of the French Open here in a late match on Tuesday.This was Greek Tsitsipas's only second win over the Russian who was looking to get to world No. 1 position. Medvedev could have become No. 1 had he won the title or even by reaching the final without current No. 1 Djokovic reaching there.The two-hour-21-minute battle saw Tsitsipas enter his third consecutive Grand Slam semi-final. He had also entered the semi-final at last year's French Open where he lost to Novak Djokovic.On Tuesday, the Greek star tennis player 73 percent of first service points and 77 percent of second service points. He also converted four out of the seven break-points he got.Medvedev, however, could convert only two out of the eight break-points he got and won 60 percent points on his first and second serves.Tsitsipas, who won 43 receiving points against just 23 by Medvedev, will now face world No. 6 Alexander Zverev who had earlier on Tuesday defeated Spaniard Alejandro Davidovich Fokina 6-4, 6-1, 6-1.This was Zverev's first entry into semi-finals of French Open.Tsitsipas, who put Medvedev under pressure in the quarter-finals right from the start, will start favourite due to better head-to-head record (5-2).