Andy Roddick, Lleyton Hewitt and David Nalbandian all spring to mind as Roger Federer's biggest concerns ahead of the Australian Open.
The world number one, however, admitted last Friday that he is more concerned about finding out something about his first round opponent, Uzbek wildcard Denis Istomin.
"I have never heard of him so I can't tell you one thing about him," Federer said of the 195th ranked 19-year-old.
On Sunday, Federer said he at least now knew Istomin is "a righty" and had a double-handed backhand.
"I think he plays from the baseline, too, maybe aggressive," Federer told reporters.
"I just read into some results of his.
"He played well in the futures and stuff. He obviously started to play on the big stages as his ranking was going up."
Istomin, who has no biographical information aside from a birth date and his ranking on the ATP tour's official website, was tracked down by an Australian newspaper on Saturday who managed to extract some details from him.
The match will be his first in a Grand Slam. When he was 16, he was involved in a serious car crash suffering a broken hip and wrist and told he would never play competitive tennis again.
He did not play for two years and even though his Federer showdown was his Grand Slam debut he is undaunted.
"For me, it's good I win, maybe," he told the Sydney Morning Herald. "I can, I wish."
His appraisal of his prospects against a man ranked 194 places higher and who has compiled a 155-10 win loss record over the last two years may be a touch optimistic, though Federer refuses to dismiss his prospects.
"[He is] definitely nobody to underestimate because we all know also guys ranked outside of the top 150, 200, they are dangerous opponents.
"I beat [Carlos] Moya when I was 300 and he was number four in the world. Everything is possible."
Though highly doubtful.
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