World number one Andy Murray beat Tunisia's Malek Jaziri in straight sets at the Dubai Championships in his first match for six weeks.
Murray, 29, was playing his first match since a surprise fourth-round defeat at the Australian Open last month.
Jaziri, ranked 47th in the world, broke Murray's serve early on but the top seed recovered to win 6-4 6-1.
Britain's Dan Evans also reached the second round with a 6-2 6-3 victory over Germany's Dustin Johnson.
Murray will face Spain's Guillermo Garcia-Lopez, who won their last meeting at Indian Wells in 2012, on Wednesday, while Evans takes on French fourth seed Gael Monfils.
Second seed Stan Wawrinka made an early exit with a shock 7-6 (7-4) 6-3 defeat by Damir Dzumhur of Bosnia and Herzegovina.