Doha: Roger Federer and fever-hit Rafael Nadal both had to fight their way out of trouble before reaching the quarter-finals of the Qatar Open.
Federer needed to recover from 4-5 down in the first set tie-breaker and from a break of serve down at 1-4 in the second against Swiss compatriot, and childhood friend, Marco Chiudinelli, ranked only 117 in the world, before coming through 7-6 (7/5), 7-5.
World number one Nadal had to survive a tight first set and the loss of his first love set in nearly two years before overcoming the inspired hitting of Lukas Lacko, the world number 83 from Slovakia, by 7-6 (7/3), 0-6, 6-3.
Both superstars were confronted with opponents who hit hard and flat and had little to lose, enabling them to attack the ball freely.
But both had reasons for being below par.
Nadal has been feeling unwell for several days and spent much of one day here resting, while Federer found it difficult to generate his usual intensity while playing against a compatriot and long-term friend.
Lacko often took the breath away with the way he hurtled around the court and hit the ball as though trying to puncture it.
Had he held on to his early break of serve at 2-1 or pushed through when he had Nadal at deuce at 5-5 later in the first set, much may have been different.
But Nadal focussed fiercely at the start of the final set, ran hard, and played solid counter-attacking percentages, and was rewarded by a far higher ratio of errors from Lacko.
"It was a very difficult match," said Nadal, who celebrated his survival with evident relief and enthusiasm.
"But I resisted. I just made up my mind to do my best in the final set. I came back but it was very tiring for me."
Federer`s survival against Chiudinelli followed a knife-edge recovery in saving three successive set points in his opening encounter against Thomas Schoorel, the Dutch qualifier, before progressing similarly in two tight sets.
"Playing such a good friend is so rare for me," Federer said. "And seeing him maybe having an injury as well, and feeling bad for him, and hopeful that he`s not going to have another injury, was really difficult.”
"We used to live walking distance from each other, and spent so much time together, and now all of a sudden we are playing together here in Qatar."
Federer will next face Viktor Troicki, a member of the Serbian team which won the Davis Cup in Belgrade last month and who reached the last eight with a 6-3, 6-1 win over Teimuraz Gabashvili of Russia.
Nadal`s next opponent is Ernests Gulbis, the dangerously talented Latvian who overwhelmed Antonio Veic, a Croatian qualifier, by 6-3, 6-1, and who will probably enjoy recalling memories of troubling Federer in a three-set quarter-final battle here last year.
Philipp Kohlschreiber, the eighth-seeded German, was beaten 7-6 (7/5), 6-7 (2/7), 7-6 (7/4) by Ivo Karlovic, the six-foot ten-inch Croatian whose serve descends from steeper angles than any player on the tour.
Karlovic, once a top 20 player, but now working his way back up from the seventies after injury, served almost as effectively as ever, not losing a service game throughout.
Nor did Kohlschreiber, which caused the contest to depend on a Russian roulette shoot-out in all three sets. It was the fifth time in five sets this week that Karlovic had taken the tussle to a tie-breaker.
Jo-Wilfried Tsonga continued his comeback from a knee injury by reaching the quarter-finals with a 6-2, 6-4 win over Sergei Bubka, the son of Olympic gold medal pole vaulter Sergey Bubka.