
The Swiss built on January’s Australian Open victory, as well as his Indian Wells success with a convincing 6-3 6-4 win over the Spaniard.
A fourth straight win over Nadal, his longest winning streak in their 13-year professional rivalry, has also made Federer the oldest winner of the Miami Open.
This means that the 35-year-old has won 19 matches this season, being defeated once so far.
He earlier won a thrilling three-hour contest against Nick Kyrgios to book a place in the finals.