Venus Williams advanced into the fourth round of the Miami Masters with a straight-sets victory over Samantha Stosur.

The American, ranked 16 in the world, was pushed hard by her lower-ranked Australian counterpart in an opening set that spanned 40 minutes.

Both players broke one another's serve in the first four games as the pair sat deadlocked on two games apiece.

However, Williams pulled out another break of serve in the fifth game as the veteran ultimately edged out Stosur 6-4 for a first-set advantage.

Williams rattled off two breaks of serve en route to a 5-1 lead in the second set, but Stosur fought back, breaking Williams twice in succession to bring the score to 5-5.

The seven-time major winner broke straight back to give herself the chance to serve for the match but Stosur had other ideas and took the set to a tie-break.

The American finally defeated Stosur in the breaker, winning all of her service points on her way to a 7-3 victory.