Great Britain waiting on Andy Murray fitness in Davis Cup Coverage: Commentary on BBC Radio 5 live sports extra from 10:00 BST Sunday, and via BBC Sport website from 13:00 BST on Saturday Great Britain are waiting on the fitness of Andy Murray for Saturday's crucial doubles rubber in their Davis Cup World Group play-off with Croatia. Murray was troubled by a back injury as he swept aside 16-year-old Borna Coric before Ivan Dodig beat Dan Evans to level the match at 1-1. Murray is due to partner Colin Fleming, with Jonny Marray on standby. GB captain Leon Smith said: "The doubles isn't until the afternoon so it give us plenty of time to assess it." Dan Evans's attractive array of strokes, and especially that sliced backhand, just don't pack the same punch on clay, and he was soundly beaten by Ivan Dodig. Dodig is Croatia's number 1 in the absence of Marin Cilic, and he looks as if he is rising to the challenge of being team leader. Andy Murray was never in any danger against Borna Coric, but the 16-year-old showed bags of class and temperament, especially in the first set. Murray says his back is sore, so Leon Smith must now decide whether he should be risked in Saturday's doubles. Murray had to work hard early on before beating Coric, the 16-year-old US Open junior champion, 6-3 6-0 6-3. The British number one, who withdrew from the French Open this year with a back injury, appeared to be suffering a similar problem in the third set. "My back is a little bit sore," he said afterwards. The change of surface is difficult, but after a couple more matches I'll have some time to rest, so let's just get the win this weekend. With the tie even, Saturday's doubles rubber will determine which team takes the advantage into Sunday's reverse singles. Smith said he would leave the final decision to Murray, and expressed his confidence in Marray, who won the 2012 Wimbledon doubles title with Fredrik Nielsen of Denmark. "Andy has been feeling his back - it's an ongoing issue," he told BBC Sport. He has good people around him and will get lots of treatment. Then it's really up to Andy. The welfare of Andy's body is far more important than this tie and we have a former Wimbledon champion who is waiting to come in should Andy not be able to play. It's not a bad situation to be in. Coric, making his Davis Cup debut, gave Murray a tough test in the first set, the second game containing a 57-shot rally. But the Wimbledon champion broke Coric in the eighth game and went on to win the next seven games, taking the second set 6-0. The Croat broke the Scot in the third, but Murray fought back to seal victory. "I thought the first five or six games were tough," said Murray, the 2012 US Open champion. I wanted to make the points long and challenging for him, physically. Maybe I was trying to play with too much spin. Once I got the break, I won a few games in a row. I lost my concentration a bit at start of the third but saw it through. It was OK - it could be better. British number two Evans, ranked 149, lost 6-3 6-2 6-3 to world number 35 Dodig. Evans, who broke into the world's top 150 for the first time after reaching the US Open third round, was outclassed by an opponent who adapted far better to the demands of clay. Dodig, who served 10 aces to his opponent's two, broke in the seventh game to take the first set and cruised through the second with a double break. Trailing 5-2 in the third, Evans saved two match points on his own serve to force Dodig to hold, which he did with some ease to level the tie. "I didn't play badly but he didn't give me anything," said Evans. It was no secret it was going to be hard and I'm glad to have three sets on that court. That will definitely help me on Sunday. The winner of the tie will qualify for the elite World Group.