Borg d. Tanner 6-4, 9-8 (7-1), 6-4
I haven't seen this one, just reading up on it.
Per Fred Tupper in the NY Times, Borg never lost his serve over 110 minutes. Tanner had 10 aces, Borg 8 aces and 8 double-faults.
Tanner said, “I played differently than I did against Connors. That was probably my mistake. I tried to chip and go in which is not my style, and he served much better than I thought, every single second serve to my backhand.”
Tupper wrote that Borg’s plan was “to serve every ball to Tanner’s backhand and, what’s more, to hit every possible stroke there, too.”
That's interesting because SI, in Moose's post, wrote in '79 that Tanner could now come over the ball with top on his BH. It held up reasonably well but that side was still where Borg drew more errors. For example, Borg served out the second set at love, with 3 serves drawing BH errors.
Tanner also made BH errors with some regularity in the rallies, including famously on match point.