In Group I, Croatia won 1-0 in Finland at Tampere with Juventus striker Mario Mandzukic scoring the only goal after 18 minutes when Finland goalkeeper Lukas Hradecky allowed a cross from Andrej Kramaric to slip from his grasp.
Croatia have seven points and lead the standings while Ukraine moved into second place after a 3-0 win over Kosovo in a game played at Krakow in Poland.
Artem Kravets put Ukraine ahead on the half-hour mark before Andriy Yarmolenko and Rustan Rotan made sure of the three points in the last 10 minutes.
Yarmolenko has now scored in six of his last seven World Cup qualifying matches.
Sunday's other early game saw Israel beat Liechtenstein 2-1 in Jerusalem in Group G thanks to brace of goals from Tomer Hemed in the first 15 minutes.