Japan's return to the Under-19 World Cup stage for the first time in six years did not exactly go to plan as they went down to a thumping defeat at the hands of Sri Lanka today in Windhoek.

After Japan's captain Kazuma Kato-Stafford won the toss and put Sri Lanka in to bat, the full member side dominated the game with openers Dimantha Mahavithana and Viran Chamuditha racking up a formidable partnership of 328 before the former was run out for 115 in the 44th over. It was a record partnership in Under-19 ODIs.

Chamuditha was out soon afterwards with his score standing at 192, the highest individual score in Under-19 World Cup history, and the second highest in all Under-19 ODIs. Captain Vimath Dinsara hit an unbeaten 44 from 24 balls to help Sri Lanka post 387-4 from their 50 overs. Timothy Moore was the only Japanese bowler to emerge with any credit, taking 3-43.

Hugo Kelly salutes his teammates upon reaching his century (ICC.TV)

Japan's reply started with Nikhil Pol falling for a second ball duck, and they were never really in the hunt from there. They did, however, manage to bat out their overs with Hugo Kelly scoring an unbeaten 101 - Japan's first century at this level, and only the third by an associate player against a full member side in the tournament's history - as they posted 184-8 from their 50 overs.

Things don't get any easier for Japan in their next match, which will be against defending champions Australia at the same venue on Tuesday. Sri Lanka are next in action on Monday against Ireland.