This was the sixth time Muguruza has played the main draw of the WTA Premier Mandatory Mutua Madrid Open, reaching the second round in 2014 and 2016, reports EFE news agency.
History seemed to be repeating itself, as Muguruza started out the match faltering and nervous, losing the first set 2-6.
Muguruza became more confident, quick and aggressive in the second set, just as she had played when she won in Roland Garros and Wimbledon, beating Vekic 6-4.
From there on, Vekic lost focus, losing the last set 6-1.
Muguruza finished the match with a total of five aces, while Vekic scored two.
Muguruza's comeback coincided with Carla Suarez's, the other Spaniard who has advanced to the round of 16, who beat Elina Svitolina 2-6, 7-6 and 6-4.
Muguruza will now face Daria Kasatkina, who defeated Sorana Cirstea 6-3 and 6-1, while Suarez will play against Bernarda Pera, who won against Johanna Konta 6-4 and 6-3.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
