Fourth seed Petra Kvitova was given a scare by qualifier Olga Govortsova in her first-round match at the Mutua Madrid Open, but came through in three sets to progress in the Spanish capital.
World number 137 Govortsova was solid in the first set, not giving Kvitova the chance to break and finishing the set on a four-game winning streak to claim it 6-3.
Belarus's Govortsova held serve to begin the second, but she then lost six games in a row as Kvitova roared to a 6-1 success to level the match.
Wimbledon champion Kvitova broke at the first time of asking in the decider and, although she was pegged back to 5-4 at one point, the Czech came through 6-4 to advance.
Kvitova will face either Sabine Lisicki or Coco Vandeweghe in the second round.