Cristiano Ronaldo went off injured in Portugal's Euro 2020 qualifier against Serbia on Monday, sparking worries for Juventus ahead of the closing stretch of the season.

Ronaldo pulled up with an apparent hamstring strain with just under half an hour played in Lisbon, immediately signalling to the bench that he needed to be replaced.

Despite his side being 1-0 down at the time, Portugal coach Fernando Santos wasted no time in sending on Pizzi in place of the captain, who headed straight down the tunnel for further treatment.

Juventus are 15 points clear at the top of Serie A, which they look set to win for an eighth straight season, and face Ajax in the Champions League quarter-finals in April.