Water polo is said to be the hardest sport at the Olympics

It is an inescapably burly sport, with nightmarish levels of physical contact. Umpires check players’ nails are appropriately filed, given the tendency for scratching. Yet on the surface at least the action is robust rather than violent.

Yes there are tussles, ducking, busy elbows and even some splashing. But there is also precise passing, balls skipping beautifully off the water to reach their target. There is a race for possession of the ball at the beginning of each quarter, a development all similar sports should steal. There are ostentatious dummies, players threatening to shoot by rotating the ball around their head as if goading a kitten.

The real action is happening underwater, where an occasionally-used camera reveals a horrible maelstrom of limbs. Constant kicks, knees into sides and the odd accidental-on-purpose pinch. The fight between centre back and centre forward is particularly miserable: a 32-minute splashy scrap of watery cuddles, frequent headlocks, carnage in swimcaps. This battle frequently seems to distract both from whatever is going on with the ball.

Ahead of Sunday’s Serbia-Croatia meeting there was an appetiser between Group A leaders Hungary and the USA. The players emerged one by one from the changing rooms as their names were announced. Team USA had some flashy hand signals, love hearts and confident points into the camera. Hungary’s team looked like they were on their way to a much-delayed appointment with their dentist. They knew it was going to be painful, but it had to be done. They duly bashed the Americans 11-8.

The Balkan derby followed, which should have been tighter, but Croatia raced into a 3-0 lead. Serbia come roaring back, the repetitively-named Filip Filipovic burying a long-ranger, and finally draw level after a well-worked move in the third quarter. 

Stefan Mitrovic made it 8-8 before a (metaphorical) suckerpunch, Croatia’s Paulo Obradovic leaving the Serbian keeper treading water with an unexpected shot from range. With Serbian heads gone it was 10-8 in no time, and finished 14-12. More misery for the 2016 gold medallists on the same day Novak Djokovic threw away the chance of a consolidation bronze in the tennis and broke his racket in anger.

Tempers were clearly fraying in the pool, too, but thankfully this match ended without a drop of blood being spilt. “It was a very difficult game,” said Croatia coach Ivica Tukac afterwards. “Serbia is a great team. But I think we played a very, very good game today. We deserved the victory.”

The tone from Serbia coach Dejan Savic was rather darker. “Bad beginning and the worst ending,” he said. “We had a little bit of confusion in our defence. I don’t remember when the Serbian team ever conceded 14 goals.” They play the other Balkan powerhouse Montenegro on Monday. Best stock up on waterproof plasters.