Simplify the following text for a Grade 9 native English-speaking person.
Original: He went on to make his international debut on 24 May 2008 in a friendly match against Moldova in Rijeka , coming on as a substitute for Niko KovaÄ in the 59th minute .
Simplified: His debut was on 24 May 2008 in a friendly match against Moldova in Rijeka , coming forbstitute for Niko KovaÄ in the 59th minute .