Nunes should have gone down the line. His throw to Gigi was bouncing and lacked pace, which gave Havertz the chance to close down quickly. Gigi should though have whacked the ball hard, first time in the direction of the other touchline rather than taking a touch. In that situation, you go safety first and consolidate your lead.
Technically the error said very little about Gigi’s ability with his feet and was simply a misjudgment of how quickly Havertz was closing in.
I have not spent ages analysing the quality of Gigi’s passes but a simple fact is that he has a very high pass completion for a goalkeeper, it was 77% overall yesterday in a game where he made 44 passes of which 20 were long ball's on which his completion dropped to 50%. Oh, and his pass completion across the season is better than Trafford’s.