As for Connors vs Lendl in general (not speaking the U.S Open here, but overall) I notice alot having Lendl above Connors. While I can understand that, I dont really agree. Both are 1-2 one way or another in alot of the same type of records, slam finals, I think were in slam semis at one point (Federer probably surpassed that by now), tournament titles in the Open Era. So all the stats Lendl is most praised for, those are also Connors biggest strengths and he matches him. Lendl from 85-87 probably seemed more dominant for 3 a year stretch than Connors ever was. However Connors from 74-76 was really similarily dominant, it just doesnt seem that way since he only won 1 major in 75 and 76 combined, but around then only the U.S Open and Wimbledon were really considered big 4 events, unlike when Lendl was on top. Connors was clearly the #1 in 76, and a toss up with Ashe in 75. Connors in 74 was far more dominant than Lendl was any single year however.
The main thing though is their matches vs each other make it hard for to think Lendl is the better player. Even at 30 and 31 Connors was still winning most of his matches with Lendl, especialy the big meetings. Lendl had to wait until almost 25 to start getting the upper hand on a now 32 year old Connors. Plus Lendl won almost all his majors after McEnroe and Connors declined in a huge way, and Borg was long gone. Connors won his majors in a much tougher era.