1989 French Open. Chang looked like he was out for the count on a number of occasions, overcame severe cramps, even served underhand but eventually won in 5 sets. Completely bamboozled Lendl.

On the other hand if you want to see what an overdose of charisma does, then watch Nick Kyrgios vs. Dustin Brown. Ridiculously good tennis but neither of them was consistent enough to maintain the form long enough to win Grand Slams (singles).
So, on the other hand you have Sinner, dull as dish-water maybe but he demonstrated an utterly dominant form of tennis yesterday and gave Alcaraz neither room nor time on the ball. Superb display.
Perhaps the most un-Italian Italian... but the only Italian to have won Wimbledon.