MELBOURNE: Fourth seed Daniil Medvedev of Russia held his nerve in a war of attrition against American Frances Tiafoe to register a 6-3 4-6 6-4 6-2 victory in the first round of the Australian Open on Tuesday. American great John McEnroe recently tipped Medvedev as the man most likely to break the Grand Slam stranglehold of Novak Djokovic, Rafa Nadal and Roger Federer at Melbourne Park after a season featuring four titles and a Tour-leading 59 match wins. Medvedev, a U.S. Open finalist last year, arrived in Melbourne in red-hot form, winning all his singles matches at the inaugural ATP Cup before a three-set defeat to seven-time Australian Open champion Djokovic in the semi-final. He broke Tiafoe’s serve three times to breeze through the opening set, but the American came roaring back to level the match in the second, displaying a never-say-die attitude in front of an appreciative Rod Laver Arena crowd.