Playing her first tournament in seven months, Karolina Muchova dealt out a 6-4, 7-6(3) upset of No.18 seed Leylah Fernandez in the second round of the Miami Open.

Muchova, who will play Naomi Osaka on Saturday, had not competed since the US Open last year due to an abdominal injury, and her ranking has fallen from a career high of No.19 last May to its current No.74. However, as in her first-round defeat of Czech compatriot Tereza Martincova, she demonstrated that her exquisite touch had not been affected by the long layoff.

US Open finalist Fernandez was making her Miami main draw debut, and coming off a solid run of form that had seen her defend her Monterrey title and reach the fourth round of Indian Wells. But the Canadian was undone both by Muchova's creative shot selection and the windy conditions, which played havoc with her overhead in particular.

Match management: The first set saw a total of nine break points between the two players, five for Fernandez and four for Muchova, but only one was converted when the latter slammed a crosscourt forehand for 3-2. Muchova also broke for 4-2 in the second set, and advanced to the brink of victory by nailing a backhand pass for 5-3.

Until then, the match had been characterised by high-quality exchanges in which both players showcased their variety and touch, particularly at net. But Muchova became error-strewn as she attempted to close out the win, and Fernandez took advantage to force a tiebreak.

A shanked forehand and a fourth double fault made for an inauspicious start to it for Muchova, but the 25-year-old righted the ship just in time to reel off seven of the next eight points.

In Muchova's words: "I'm dead!" Muchova said with a laugh in the on-court interview. "[After an injury] you can do whatever fitness, but the match is something else. For me it was a win just to play and compete again."

Miami: Muchova marks comeback with upset of Fernandez

Collins returns from injury with three-set win over Bondar

No.9 seed Danielle Collins scored her first win since reaching the Australian Open final over Anna Bondar 6-3, 3-6, 6-4 in 1 hour and 57 minutes.

The American, a semifinalist in Miami in 2018, had retired in the first round of Dubai due to dizziness and withdrawn from Indian Wells due to injury. Collins quickly shook off her rust after getting broken in the opening game, breaking Bondar back immediately and dropping only three more points on serve in the first set.

Highlights: Collins d. Bondar

But the No.76-ranked Hungarian began to show off her own formidable serve as she hit back to take the second set, and lead by a break at 2-1 in the third. Collins responded by reeling off five straight games; though she was unable to serve out the win, two double faults from Bondar in the final game, including one down match point, enabled Collins to advance.

Another American, Alison Riske, joined Collins in the third round after defeating No.31 seed Alizé Cornet 6-2, 6-2 in 1 hour and 26 minutes. Riske maintained her perfect record against the Frenchwoman, to whom she has not dropped a set in seven meetings dating back to 2011.