Murray struggling to find his form as Del Potro lies in wait
Andy Murray huffed and puffed before booking his place in round three of the French Open with victory over Martin Klizan.
The first set on Court Suzanne Lenglen was a horror show for the World No.1 against a player who almost skipped Roland Garros because of a calf injury.
But Murray turned things around to win 6-7 (3-7) 6-2 6-2 7-6 (7-3) and set up a third-round clash against former US Open champion Juan Martin Del Potro.
It is tough to see Murray winning that one without a significant improvement in his form, although Del Potro was struggling physically before second-round opponent Nicolas Almagro was forced to retire with a knee injury.
After three hours and 35 minutes on court, Murray said: "I expected it to be very tough. He (Klizan) goes for huge shots and on his forehand, he can hit winners from anywhere.
"Sometimes you think you've hit a good shot and he comes up with unbelievable power. It's very tough. I tried to play solid, as the match went on I tried to hit the ball deeper and was controlling more of the points."
Murray finished his first-round match against Andrey Kuznetsov with a run of eight games in a row and with the mood cautiously optimistic.
Having arrived in Paris short of wins and confidence, Murray was hoping the best-of-five-set format and relatively kind draw would allow him to play himself into form. But any confidence he had gained swiftly evaporated as Klizan, ranked 50th, took an early hold.
Muttering about his movement, Murray was passive and error-strewn, allowing his opponent to dominate with his big forehand.
Murray looked to have turned a corner when he broke Klizan as he served for the first set at 5-4 but the Scot then played an awful tie-break.
Even when he won the second set with a run of five straight games, there were plenty of alarm bells ringing.
Klizan's play had become a lot more erratic, and Murray extended his winning streak to seven games at the start of the third set and finally seemed to be finding a bit of rhythm.
Two points in the opening game where he turned defence into attack were reminiscent of Murray at his best but, although he took the set, we were still a long way from that.
Murray was consumed by his own frustration as he got bogged down in the fourth set.
Chuntering away to himself, his box and the umpire, he lost the first three games despite having chances to win all of them.
Klizan veered from appearing to be on his last legs one minute to sprinting full pelt the next, producing some fine shots when he most needed them and torturing Murray with drop shots.
But, as in the first set, he could not serve it out, and Murray should have made it two straight breaks in a long 11th game.
He continued to do things the hard way but Klizan's resistance finally came to an end in the tie-break and Murray took his second match point with one of his best shots, somehow digging out a forehand winner.
Kyle Edmund, meanwhile, reached the third round for the first time with victory over Argentina's Renzo Olivo.
The British No.2 is yet to drop a set at Roland Garros this year and blasted to a 7-5 6-3 6-1 win in two hours and two minutes.
Olivo produced one of the stories of the first round with his upset of French favourite Jo-Wilfried Tsonga but things were rather different away from the limelight on Court 6.
It will not have seen many bigger forehands than Edmund's and Olivo was left helpless.
Edmund is ranked 42 places above his opponent and made that show, looking confident and composed even when he failed to serve out the first set.
Edmund promptly broke again in the 12th game and did not look back. The only thing that held up the 22-year-old in the third set was a medical time-out for his opponent.
This is the second time Edmund has made the last 32 at a Grand Slam. At last year's US Open he defeated Richard Gasquet and John Isner before losing to Novak Djokovic.