Luis Enrique's side were not entirely convincing but got their win at the third time of asking, with Switzerland unable to respond to Sarabia's 13th-minute strike
Luis Enrique vowed to rotate after Spain's opening Group A2 stalemate with Portugal and made eight changes in Prague, where Jakub Pesek struck after just four minutes
Euro 2020 qualifiers Finland momentarily topped the group with nine points from four games, two ahead of Wales, who later took first place with 10 points after beating Bulgaria.