Andy Murray was satisfied to survive the blustery Florida conditions and ease past Bernard Tomic in the Miami Masters.
The Briton overcame a few early jitters in the 56-minute 6-3 6-1 victory as the Australian faded badly.
"I didn't hit it great but I worked hard," said Murray who will leapfrog Roger Federer for the world No 2 spot if he takes the title.
"No matter how you start your match you need to make your opponent work hard. Once I got ahead, I played consistently. I served pretty well and didn't give him too many opportunities.
"I got the breakthrough and he made mistakes but it is unbelievably hot and windy. It's tough to feel comfortable, maybe more than my opponent because I am used to the court and the wind and the humidity."
Tomic, ranked 45 in the world, even had to endure a few jeers from the American crowd as he struggled badly after enjoying a fizzing start with three break points.
It was a disappointing show for the Australian who overcame five players above him in the rankings on his way to a tournament win in Sydney in January.
"A few days ago I got sick," Tomic admitted. "I felt OK until I started to warm up. My body didn't react well and I found it difficult to breathe.
"Andy played well and against a player like that you have to play well, but unfortunately I didn't have the game to do that."
Murray will next face Grigor Dimitrov in the third round after Italy's Simone Bolelli retired against the Bulgarian.