Verified answer

He reminds me a lot of the type of player who has a strong game against every other player on the tour, except the top guys. And that is not to say that he does not have much of a game because clearly he does. It's just that when it comes to the Federer's and Nadal's and Roddick's of the game, he really does not match up well against these guys. He may push them a little in matches and perhaps even eke out a win on a day when perhaps they are not playing their best tennis, but for the most part, his game does really match up well with theirs.

The big part of his game and the reason why he has been rank so high in the top 10 for the past few years, is the consistency to which he brings to his game. Davydenko is one of the few players who players nearly every week, and because he is so consistent, winning more matches than losing, he has been able to keep his ranking high.

He is like the Elena Dementieva, or Daniela Hantuchova or even the Jelena Jankovic of the men's game. They may not have enough of a game to consistently produce upset wins over the top players, but their strength in playing consistently on the tour helps them to have a high ranking.

So I don't think that he has either over-achieved or under-achieved. I believe he has been able to achieve all that he is meant to achieve in the game. But we will never know the answer to this question because given what this guys has been through the last 12 months concerning the betting scandal, which he has been officially cleared off finally as of today, there is just no telling how much of an impact this has had on his game these past 12 months.

Under Achiever he got to no. 4 in the world (somehow) but he is inconsistent. He does terrible at Wimbledon and has never won a Grand Slam. Andy Murray is now in the deserved no.4 spot.