Novak Djokovic wasn't optimistic about his right ankle injury after lifting Serbia to an insurmountable 3-1 lead over the United States with a 7-5 6-7 (7-4) 6-1 6-0 win over Sam Querrey in a Davis Cup quarter-final.
The world No.1 twisted the ankle while hitting a forehand in the third game of the match on Sunday.
"Injuries are part of the sport and you try to avoid them as an athlete as much as you can," Djokovic said. "The nature of the injury is still to be determined.
"One hour, one hour and a half after the end of the match, all I can say is it doesn't look good."
Djokovic had the ankle tightly wrapped and had taken anti-inflammatory pills. He plans to travel home to Monte Carlo to have an MRI scan.
He was hoping to be ready to play the Monte-Carlo Rolex Masters, which he considers his home event, but didn't sound convinced he'd be ready to play when it gets underway April 14.
"It's swollen, and when it's swollen it's definitely not a good first sign," Djokovic said. "I'm going to do everything I can in my power to recover till that tournament. How realistic that is, I don't know what to tell you."
Djokovic indicated that the consequences of playing on the ankle didn't enter his decision in continuing with the match.
"I was just thinking of just winning this match and bringing the tie win to Serbia and I'm glad I did," he said. "On the other hand, I'm a bit concerned it's not comfortable feeling what I feel with the ankle.
"If it was a normal ATP Tour event, I don't know. But probably my mindset would've been different. I had a lot of motivation and it just felt logical that you do your best to finish the match.
"Luckily it was a win."