Andrea Petkovic has sealed a place in the third round of the Miami Open with a 6-2 6-2 triumph over American Christina McHale.

Both players lost serve in the opening set, but it was Petkovic who was able to bounce back with a double break to take the lead in the United States.

Momentum swung rapidly in the second set as McHale struck first to go a break up, but her German opponent immediately responded with a break of her own.

Both competitors struggled as they each lost serve in their next games, but once again, Petkovic managed to come through with another double break, which won her the contest.