Hard work is not talent according to the dictionary
Appeal to authority, but having the ability to work hard and for an extended period of time can be a talent in itself.
The definition you gave,
"a special ability that allows someone to do something well" doesn't exclude someone's intrinsic capacity to furnish hard work as a talent... in that sense, that person's talent would be to do just that, easier and better than others.
A greatest example of that in my opinion is certainly the pianist
Yundi Li. He never had any natural predetermined skills for music and piano for a start in comparion to the Martha Agerich or Valentina Lisitsa but his talent resided in his capacity to work really hard, alone, to the extreme and for such an incredible extended period of time... that he became so talented in playing the keyboard that he ended up winning the great
"International Chopin Piano Competition" in 2000.
I think talent for a start is something somebody is just good at doing naturally without no specific external intervention from other people -; and then, because of the fact of living in a society, that talent is polished... by the those who believe that there's a possibility to make something (great) out of it. Actually, most productions (I don't really have another word that comes in mind right now) that comes from a human being can be a talent for a specific individual.
Where talent becomes quickly overrated is when people attribute or perceive greater elements to the actual true level that it should be in a given individual -; in tennis, God knows how many players have gone through that phase where a small group of people taught they had seen something, sold the merchandise to a bigger group, only for them to realize (anyways a majority) that the person was simply just no that good.
I suspect however that the media, because of their role to continuously sell, talk about players etc. do bring people (who are generally not aware about the overall technical and else elements of the game) to see things in certain players (over a very few amount of matches) that do not exist enough on a longer period of time to state that the person in question is a tennis talent ; but that's another debate.