I'm reading in Steve Flink's "Greatest Matches of the Twentieth Century" that Mac served at 70%, just below his Wimbledon final percentage, in his 5-set match against Connors at the Open. 75% over three sets at Wimbledon is great, but 70% over 5 sets may be even more remarkable.
are you sure about this? I recall Mac's 1st serve % being quite low in that match(maybe even less than 50%) which is why he was broken so much that day.
I find it hard to believe that Mac could serve 70% & get pushed that much, the serve was the most important part of his game.