Former Monte-Carlo Masters champion Stan Wawrinka kicked his 2019 campaign off with an impressive win as Grigor Dimitrov also progressed.
Wawrinka, who won the title in 2014, required just one hour and 15 minutes to ease past Lucas Pouille as he secured a 7-5, 6-3 victory.
The Frenchman actually had the early advantage as he broke early, but Wawrinka claimed two consecutive breaks in games 10 and 12 as he won the final four games of the set.
An early break in the second set was enough for the Swiss to ease into the second round.
Former ATP Tour Finals champion Dimitrov was too good for Matteo Berrettini, winning 7-5, 6-4 in just under two hours.
The Bulgarian lost the opening game of the match, but broke back in game four to draw level at 2-2 and then claimed the important break in game 12.
It was a similar story in the second set as the duo shared breaks before Dimitrov got the job done with a break in game 10.
Borna Coric also booked his place in the second round with a 6-4, 5-7, 7-5 win over Hubert Hurkacz while Guido Pella came from a set down to beat Laslo Djere 6-7 (2-6), 6-2, 6-4.
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