British captain Leon Smith says whether or not to recall Andy Murray for Friday's quarter-final against Germany at the inaugural Davis Cup finals is one of his "more difficult decisions".

Murray, 32, was rested for the Group E victory over Kazakhstan which booked their last-eight spot in Madrid.

With Britain facing the Germans at 16:30 GMT, Smith says he will make his decision in the morning.

"Andy is a team player and understands what is best for the team," he said.

Former world number one Murray looked sluggish as he laboured to a three-set win over Dutch world number 179 Tallon Griekspoor in the opening group match on Wednesday, admitting afterwards he was still "a couple of kilos" heavier than he would have liked after gaining weight while taking time off with his new-born son and family.

In the Scot's absence, Kyle Edmund played one of his finest matches of the year to beat Kazakhstan's Mikhail Kukushkin before Dan Evans was overpowered by Alexander Bublik in three sets.

British number one Evans, 29, is yet to win in the Madrid finals, although Smith is backing the 29-year-old to "find a way" to win.

Following 24-year-old Edmund's performance, it appears likely Evans will make way for Murray's return - if Smith decides he is in good enough shape.

"There is no awkwardness about who is going to play, who isn't going to play, it is a good, open and honest discussion. That's what we will do again," Smith said.

"It might be one of the more difficult decisions I've had to make, but it is also better when you have got the quality we've got to be able to have those discussions.

"We can look at who is in the best physical condition, and look at the match-ups again, linking those factors together to do what is best for the team.

"Because we are scheduled tomorrow evening it gives us time to see if everybody is right and how they feel."

Germany reached the quarter-finals by topping Group C, winning five of their six rubbers against Argentina and Chile.

Philipp Kohlschreiber, their experienced second-ranked singles players, has dropped one set in his two victories, while leading player Jan-Lennard Struff is ranked higher than any of the British players at 35th in the world.

Struff dropped their only rubber in a three-set loss to Chile's Cristian Garin on Thursday with French Open champions Kevin Krawietz and Andreas Mies showing their class by cruising through the doubles matches.

"I think it will close, a 50-50 match again, although we shouldn't have anything to fear," Smith added.

Who else is in the quarter-finals?

Barcelona footballer Gerard Pique has overseen the transformation of the 119-year-old competition into a season-ending 'World Cup of Tennis', which saw the 18 nations split into six groups of three.

The six group winners automatically qualified for the last eight with the two best-placed runners-up joining them.

The quarter-final line-up is:

Australia take on Canada later on Thursday in the first last-eight tie, with the other three matches taking place on Friday.

Serbia face Russia from 09:30 GMT while Friday's other two ties are both due to start at 16:30.

Scheduled start times of both sessions have been moved forward 30 minutes after late finishes earlier this week, with a tie between Italy and USA concluding at 4:04am local time on Thursday. In addition, the break between the first and second singles rubbers has been cut from 20 minutes to 10.

The same start times will be in place for Saturday's semi-finals.