I agree that Borg's 1978 was the most dominant performance in an induvidual slam (at least in the open-era). The number of bagels that Borg dished out in tournament was incredible. Borg won 2 matches in which he lost just 1 game in each. Borg's final crushing Vilas was exceptional. People take it for granted that Borg would beat Vilas, but remember that Vilas was also a great clay courter. Vilas still holds the open-era record for most clay court tournaments won and several long streaks on clay.
I don't stand by this number of games lost in the tournament as definitive though. McEnroe made the top 10 without even winning the tournament. Great as I have stated Vilas was it is misleading to think that his 2 slams were 2 of the most dominant slam performances ever.