* Azarenka suffers troubling injuries
* Stephens saves five match points (Recasts, writes through)
By Greg Stutchbury
MELBOURNE, Jan 24 (Reuters) - Victoria Azarenka brought Sloane Stephens's Melbourne Park fairytale to an end on Thursday, setting up an Australian Open final against Li Na, but the defending champion came under fire for taking an injury timeout just as her nerves appeared to desert her.
Azarenka looked to have injured her left knee early in the second set of her 6-1 6-4 victory over the American teenager, but did not seek medical treatment until she blew five match points while serving for the match at 5-3.
The world number one used the medical timeout to have a rib and knee injury checked, though in a courtside interview after her win she made no mention of the injuries and said her frayed nerves had almost prompted "the choke of the year".
At her post-match media conference Azarenka was bombarded with questions about the incident as reporters asked if she had exploited the injury timeout rules to help settle her nerves.
Former U.S. player Pam Shriver also attacked Azarenka on her Twitter page, calling the injury a "charade" and that the rule should now be changed.
"I'm telling you what happened right now honestly, that my back was bothering me," Azarenka said. "It took me too long of a time to call the trainer, which was my mistake.
"I took it to the point where I couldn't breathe, which was causing from my back problem, and I couldn't really figure out what was going on on the court.
"When the trainer told me that was the rib that was blocking that, my back, that's what happened."
The 2012 Australian Open champion said her on-court comments could be attributed to misunderstanding the question in the heat of having won the match.
The rib injury was also affecting her breathing, which was "freaking her out" and the panic she experienced was to do with that, rather blowing the match points.
"I was really panicking, not because I couldn't convert my match point. That's not the case," she said.
"I'm experienced enough to go over those emotions. But when you cannot breathe, when something's really blocking you, the stress, that was the stress I was talking about.
"I just couldn't realise what was going on with me."
Until the point when she received treatment, Azarenka had been coasting against the 19-year-old Stephens.
Hailed as the future of American women's tennis, Stephens caused the biggest upset of the tournament less than 24 hours earlier by beating 15-times grand slam winner Serena Williams.
The confident teen, however, appeared nervous and Azarenka attacked her serve, breaking her seven times and winning the important points of the match from the baseline.
After she slid and twisted her knee early in the second set, Azarenka's frustrations increased when the 29th ranked Stephens saved five match points with the Belarusian serving at 5-3.
The 23-year-old world number one, however, took her timeout and forced Stephens to wait for almost 10 minutes while her back was re-adjusted, which stopped her rib from pushing on her diaphragm.
The delay seemed to settle Azarenka and she sealed her place in the final on Stephens's next service game, and sixth match point, when the American's backhand sailed over the baseline.
Stephens said the delay had no impact on the outcome of the match.
"When you take a medical break or timeout, obviously it's for a reason. Just a normal, routine break, medical timeout," Stephens said.
"It's happened before. I've had in the last match, the match before, medical breaks, go to the bathroom, the whole showdown.
"It was just something else, but it didn't affect anything, I don't think." (Editing by Peter Rutherford)