The Blues are the champions of the 2016/17 season
The goal was all the North London club needed to record a 1-0 victory over a tough West Brom side away at the Hawthorns.
It was the 23-year-old Belgian's second goal in 18 Premier League games this season, and arguably the most important in his career yet.
Anthonio Conte's men have now wrapped up the title with two games to spare, establishing a 10-point lead over closest rivals Tottenham Hotspur, who play Manchester United on Sunday.
The win represents the Blues' third league triumph in the last seven years.