World number one Andy Murray beat Tunisia's Malek Jaziri in straight sets at the Dubai Championships in his first match for five weeks.
Murray, 29, was playing for the first time since his fourth-round defeat at the Australian Open last month.
Jaziri, ranked 51st 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 Brown.
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.
"I was not good enough," Wawrinka told the ATP.
"I think I started well, but it was a tough match, missing a little bit something to push a little bit more to be a little bit more active. I think after coming back after one month out, I had to recover from the (right knee) injury."
Fifth seed Tomas Berdych led 6-3 2-1 when fellow Czech Lukas Rosol retired with a knee injury.
Despite a first-serve percentage of just 40%, Murray was satisfied with his first match back, saying: "I was a little bit uneasy, I've never hit with him or played against him before.
"It took a little bit of time to get used to his game."
The Scot had been laid low with a bout of shingles following the Australian Open, and revealed that it was his mother-in-law, Leonore Sears, who diagnosed the problem.
"I had a little bit of a rash from my bum round to my stomach," said Murray.
"It wasn't terrible. Normally if you have a little bit of a rash and you scratch it it feels better. With that it was really, really painful.
"I didn't think much of it at the beginning, but it was actually my wife's mum (who diagnosed it).
"We were having dinner and I said 'this is really irritating me' and she was like 'pull your pants down and show me, it might be shingles' and I was like 'OK'.
"And then the next day I got the doctor and she was right."