We were talking about this in my tennis class today and my coach told us back when Connors was dominating at number one, his game was something like this:
Average groundstroke speed - 40mph
Average height of groundstrokes was 6 feet above the NET
Average groundstroke placement was 18 inches inside baseline.
I cant remember any more specific numbers, but he played like the lines were six feet inside the court on each side, his unforced errors were very low, and his opponents were very high. IMO, a counter puncher is one who thrives on the opponents unforced errors, always makes them hit one more shot, places the ball deep, stays at the baseline, doesn't go for winners.