Grigor Dimitrov survived a scare against Mischa Zverev to continue his stunning start to 2017 at the Rotterdam Open, where Dominic Thiem won a battle of the rising stars with Alexander Zverev.
Australian Open semi-finalist Dimitrov lost the first set against Mischa Zverev - conqueror of world number one Andy Murray in Melbourne - but battled back to come through his first-round clash 6-7 (4-7) 6-2 6-4.
Dimitrov's win takes his record for 2017 to 15-1 and sets up a second-round meeting with Denis Istomin, the man who stunned Novak Djokovic at the Australian Open.
The Bulgarian dominated in the second set after losing the first on a tie-break. And he struck the decisive break in the seventh game of the decider to ensure progression.
Unseeded Alexander Zverev raced into a 4-0 lead and had no problems closing out the first set against second seed Thiem.
But the world number 18 could not maintain his momentum from the opening stages as Thiem, who won 82 per cent of his first serve points, mounted a fine fightback to win 3-6 6-3 6-4.
Third seed David Goffin had no such difficulties in his 6-3 6-2 defeat of Andrey Kuznetsov and sixth seed Jo Wilfried-Tsonga saw off Gilles Muller 6-4 6-2 in a second-round contest.
Richard Gasquet cruised to a 6-4 6-2 victory over Viktor Troicki in his opener while there were also wins for Martin Klizan and Pierre-Hugues Herbert in the two other second-round encounters.