Top seed Stanislas Wawrinka is four wins away from claiming the Miami Open title after defeating Malek Jaziri in the third round.
The world number three overcame his Tunisian opponent 6-3 6-4 in one hour and 11 minutes to reach the final 16 of the tournament.
Wawrinka put pressure on Jaziri's serve early in the match, but he failed to convert two break points to give himself an early advantage.
The 32-year-old eventually found a way through to go 4-2 up before sealing the set and taking an early break point in the second, which put Jaziri on the back foot.
The world number 53 tried to unleash a comeback, but he failed to convert four break points, which allowed Wawrinka to push on and wrap up the match.