Mathews made his debut for Sri Lanka Under-19s when he was just 16 years old, against Pakistan in 2003. He is an outstanding allrounder, capable of batting anywhere in the top order and also delivers lively medium pace.

A fixture in the youth side since his debut, he was handed the captaincy for the 2005 tour of England. The highlight on that tour was an unbeaten 123 in the third Test which wasnot enough to stave of defeat. During the U-19 triangular series involving Bangladesh and England towards the end of 2005, Mathews produced a series impressive, mature innings with the bat. An unbeaten 70 set up a win against England and he followed that with 97 not out, in a defeat, against Bangladesh.

After a quiet debut first-class season, in 2007-08, he made big strides with 696 runs at 58 and carried his good form in to Sri Lanka A's tour of South Africa. His performances there won the praise of the coach, Chandika Hathurusingha, who identified him as one for the future. He made it to the national side for the tour of Zimbabwe in 2008.