BELGRADE, June 18 (Xinhua) -- The FINA Water Polo World League Super Finals opened in Belgrade on Tuesday with wins from current world champions Croatia and Olympic champions Serbia, as well as a rain storm.

In the first match this afternoon, Croatia dominated over Kazakhstan by 20-4 (5-2, 6-0, 3-0, 6-2), while Croatia's Vukicevic shined with four goals.

In the second match Canada surprised the runner-up of last year's super final Hungary by 10-9 (3-1, 2-3, 4-3, 1-2), thanks to an extra player in the pool in the final moments of the match.

Spain easily defeated Japan 18-10 (3-3, 6-3, 5-1, 4-3).

The fourth match between Olympic champions Serbia and Australia was interrupted by heavy rain at the open venue in Belgrade. After the one-hour break, Serbia won by 12-8 (4-5, 3-0, 4-3, 1-0).

Eight of world's best national teams gathered in Belgrade for the FINA Water Polo World League Super Finals, running from June 18 to 23.

The winners will get the early ticket for the upcoming 2020 Summer Olympics in Tokyo.