If there's anything we've learned from many years of observing comedy football goalkeeping virals, it's that concentration must be maintained at all times, even when the ball is miles away from your goal, with seemingly no imminent danger whatsoever.
However, we'd have thought that keeping your eyes on the ball when it's just outside your own penalty area is something of a given for any goalkeeper, yet Chongqing Lifan netsman Sui Weijie failed in even this basic duty during a recent Chinese Super League match.
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Lifan were leading 1-0 with just seven minutes left on the clock, when their opponents Liaoning were awarded a free-kick on the edge of the area. They then took it quickly, before Lifan had had chance to organise - as the rules allow them to do - and when midfielder Ding Haifeng emerged from a group of flat-flooted defenders, he found that the goal was unguarded due to Weijie casually having a sip of water next to his far post. Haifeng duly slotted in to the apparent astonishment of Weijie.
He has since been fined 50,000 yuan (£5,233) and may be suspended by his club, after supporters angrily confronted him at Liaoning's Shenyang airport.
Water mistake to make - watch it below.