Cilic broke down in tears at 6-4 3-0 down and was spoken to on court by a doctor.
It was unclear what exactly had gone wrong with the doctor returning again at the end of the set, which he lost 6-1.
Becker, working for the BBC, said: “We’ve got an explanation of what went wrong.
“He had a huge blister on his foot and couldn’t walk anymore.
“I hope they’ve fixed it.
“I just hope for the sake of the spectators the final will be more of a match now.”
A medical timeout was called at the end of the set, during which Cilic had strapping removed and reapplied on his foot.
Appearing alongside Becker in the commentary box, Andrew Castle said: “There’s a certain amount of turmoil in his head now.
“He’s a little embarrassed. It’s only been going on an hour and 18 minutes.
“He’s a little disappointed with how hes playing so far.”
