“In any sport, you need to think of today, not of tomorrow,” the 18-year-old said afterwards. “I did my best. That’s tennis, that’s sport, you need to give your best every day.”

The match was a dead rubber, with Fonseca already securing the top spot in the Blue Group with his wins over Arthur Fils and Learner Tien – and knowing he would face Luca van Assche in the final four.

But Mensik came into the encounter having not picked up a win thus far in the tournament, and served excellently in the first set to take an early lead.

Yet Fonseca is on fine form in Jeddah and bounced back quickly, despite requiring some treatment on his upper right arm after the second set.

The first break of serve came in the fifth set as the Brazilian broke in the first game – but Mensik grabbed the second to force a match tiebreak.

Fonseca was not to be denied, and completed his unbeaten round-robin stage.