* Belarussian second seed in agony after bad fall
* Wins match despite limping for much of second set (Updates with quotes, details)
By Sonia Oxley
LONDON, June 24 (Reuters) - Second seed Victoria Azarenka fought through the pain barrier after a nasty fall that left her in shock to beat Maria Joao Koehler 6-1 6-2 and reach the Wimbledon second round on Monday.
The Belarussian had cruised through the first set against the Portuguese world number 106 and was one point away from going 2-0 up in the second when she slipped behind the baseline while trying to reach a shot and almost did the splits.
"It happened so quick in the second that my leg just kind of collapsed," she told a news conference. "I felt like my knee just turned to the other way and it was just so nasty.
"I was in such shock. For two minutes I had such a consistent pain that it just completely freaked me out what happened."
Azarenka screamed in agony as she lay on the grass, with some spectators taking a moment to realise the noise was pain rather than the usual shrieks that accompany her every shot, and she received treatment there before taking a medical timeout.
Her right knee was strapped and she walked gingerly back to continue the match, serving two double faults immediately before eventually losing the game.
On top of her injury, Azarenka was hampered by a faulty scoreboard flickering in her line of sight but she overcame the distractions to break back immediately and then hold serve.
Hobbling between shots and unable to run for anything that landed far from where she was standing, Azarenka managed to win games thanks to Koehler's errors and her own power on the shots she could get behind.
Koehler nearly slipped herself on the same patch of grass where Azarenka tumbled earlier but kept her balance and held her serve.
That was the last game the Portuguese won, though, as she failed to find the drop shots or tight angles that Azarenka would almost certainly have never reached.
"I think, first of all, it's quite difficult to make a lot of drop shots against my game," the 23-year-old Azarenka said when asked why Koehler had not managed to do more to capitalise on her opponent's limited mobility.
"I really went for my shots. I felt like I had to be aggressive, to finish as quick as possible."
Australian Open champion Azarenka was visibly relieved when she finally won the match to earn a meeting with Italy's Flavia Pennetta in the next round but before that she will have more checks on her injured knee.
"It's good to have tomorrow to recover," she said. "But I still need to make the final assessments."
Azarenka had faced hostility from fans over a controversial timeout in January's Australian Open semi-final against American Sloane Stephens after she had blown five match points, but this time she received only sympathy from the Court One crowd.
Asked what went through her mind while she was sprawled on the ground, Azarenka said her thoughts went much further than wondering if she would have to pull out of the tournament.
"It was beyond what can happen on a tennis court, or should a player play," said the world number two, who has won back-to-back Australian Open titles and whose best performances at Wimbledon were semi-final appearances in 2011 and 2012.
"At that moment, it's so shocking because you have no ground. You basically just fall. Your legs go one way, and there is no balance or anything. Nothing I could control in that moment, and that's scary." (Reporting by Sonia Oxley; Editing by Ken Ferris)