The Croatian veteran lost just 11 points in his service games, never facing a break point and converting both chances he created on the return to secure the win in straight sets.
The youngster served at 70% and he had nine great holds, doing his best to create at least a glimpse of a chance on the return but that turned to be the mission impossible against one of the greatest servers in the history of the game.
Karlovics initial shot worked like a charm right from the start and he endured a baseline rally against one of the most promising youngsters on the Tour in game five to grab a break following a forehand error from Felix.
The world no. 100 confirmed the break with three service winners in the next game, moving 5-3 up with four winners in game eight and the set was in his hands after four unreturned serves in game 10 after half an hour. Both players served well in set number two, reaching 5-5 in no time at all before Karlovic shifted into a higher gear, winning 12 of the last 14 points to cement the triumph and book the place in the second round.
Serving at 4-5, Ivo hit three winners to stay in the set and he made the crucial move with a break at 15 in game 11 after three forehand errors from Auger-Aliassime and a double fault that sealed his fate in this encounter.
Serving for the win at 6-5, Karlovic landed three direct points to secure the win, pumped and motivated to make more damage in the draw ih his serve continues to work like today. Thiago had his chances in the opening set, wasting five break points and losing the tie break 7-5 before suffering two breaks in set number two that saw his chances fading away.
Benoit had to dig deep already in the third game when he saved three break points and the additional two in game five to stay on the positive side of the scoreboard before squandering two set points on the return in game 12.
The Frenchman won the tie break with a volley winner and he moved ahead with a break in the third game of the second set, controlling the scoreboard after saving both break points in the eighth game and claiming the win with another break in game nine to reach the last 16 and earn his 13th win at India Open.
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