Rotterdam - Grigor Dimitrov reached the second round of the Rotterdam World Tennis tournament with a 6-7 (4/7), 6-2, 6-4 win over Mischa Zverev on Wednesday as the red-hot Bulgarian racked up his 15th win of 2017.
Dimitrov, who captured his second title of the season last weekend on home ground in Sofia, had to dig deep, however, to see off Zverev who stunned world number one Andy Murray at the Australian Open last month.
The 25-year-old Dimitrov improved to 15-1 on the season and will next face Denis Istomin, who beat Novak Djokovic in the second round in Melbourne at the season's opening Grand Slam.
Dimitrov, the fifth seed, took victory in just under two hours, firing his 11th ace for a match point and breaking on four of nine occasions.
"I'm pleased with the win. Mischa did not make it easy for me with his game. I had to fight to win," said Dimitrov, who was champion in Brisbane and a semi-finalist at the Australian Open in January.
Belgian third seed David Goffin comfortably beat Andrey Kuznetsov 6-3, 6-2
"I am feeling good. I'm playing really well and pleased with the victory, especially against Andrey -- a good indoor player," Goffin said.
"He can play fast, so it was not an easy first round. I served well when I needed to and I am happy to win my first match in Rotterdam. I had a great week in Sofia (finalist against Dimitrov) and I've come here with a lot of confidence.
"I remember the first time I played in Rotterdam and I didn't win any games against Jarkko Nieminen (in the 2013 first round). The tournament isn't far from Belgium and I have support here."
Richard Gasquet put out Viktor Troicki 6-4, 6-2, ending with a pair of picture-perfect backhand passing shots.
In the second round, defending champion Martin Klizan battled to a 6-7 (5/7), 6-4, 6-1 defeat of 2016 semi-finalist Philipp Kohlschreiber.
Frenchman Pierre-Hughes Herbert advanced past qualifier Evgeny Donskoy of Russia 6-2, 7-6 (7/4)