Novak Djokovic revealed after the match that he wasn't feeling that great during the match but he pulled through against Fritz.
It was a tricky match for Djokovic but he handled it pretty well downing Fritz in two sets. The second set was quite close because Fritz served for the second set but Djokovic was able to pull it out and then win in the tiebreak. It's a big win for him considering the circumstances:
“I had to fight to survive. I didn’t feel
very reactive today or very comfortable. I knew coming into today’s
match from yesterday’s gruelling battle against [Daniil] Medvedev I knew
it would take me some time to adjust and find the dynamic movement I
need against Fritz, who is one of the best servers on the Tour."
He added:
“I had to be very patient, I didn’t start the second set very well. But I managed to break his serve at 5-4 when he was
serving for the set, like when [Daniil] Medvedev was serving for the
match yesterday. In those moments I find another gear and managed to
hold my nerve and make him play another shot in the tie-break."
He concluded with:
“I am very pleased to have overcome this one as I don’t think it was
one of my best days with my tennis, but I managed to hang in there.”