Ronaldo's 34th-minute goal proved the winner, as the Portugal captain turned in Nuno Mendes's cross for his milestone goal.

Roberto Martinez's side led inside seven minutes through Diogo Dalot, and 39 year-old Ronaldo forced a brilliant reflex save out of Dominik Livakovic 15 minutes later.

Livakovic was helpless to prevent Ronaldo putting Portugal ahead, though Dalot's own goal four minutes before half-time set up an exciting second period in the League A Group 1 contest.

Yet despite shading the expected goals (xG) value in the second half, with 0.44 to Portugal's 0.36, Croatia found no way through, with Ronaldo going off to a standing ovation when he was substituted late on.

Portugal, the 2019 Nations League winner, will remain in Lisbon to welcome Scotland on Sunday while Zlatko Dalic's Croatia side will look to bounce back against Poland in Osijek on the second matchday. 

Ronaldo was already the top scorer in the history of the game, and international football's record goalscorer added another to his remarkable tally to hit the 900 mark.

It was his 131st for his country, on a night he had a joint team-high four shots, along with Bruno Fernandes.

The rest of his goals have been split across his clubs: 450 for Real Madrid, 145 for Manchester United, 131 at Juventus, 68 for Al-Nassr, and five when he played for Sporting CP at the start of his career.