Earnshaw has found life difficult at Derby under two managers

Earnshaw has started just six games and made 14 substitute appearances since his club record �3.5m move from Norwich last summer.

The 26-year-old was also left out of John Toshack's Wales squad for next week's friendly in Luxembourg.

But he said: "I'm three times a better player because I've learned so much."

Earnshaw, who has scored just one goal for Derby this season compared to 27 goals in 47 appearances for Norwich, puts that down to playing against better opposition.

606: DEBATE Give your thoughts on Robert Earnshaw's future

"When you play against one of the best teams in Manchester United as we did on Saturday (losing 1-0) and you push them to the limit, that's a measure of where you are," he said.

"I've been very pleased with my performances in all the games in which I've started, and I'm very glad I've not let myself down.

"But I've learned a hell of a lot, and in games such as the one against United and against Manchester City a couple of weeks ago, I've showed what I'm about.

"I've done myself justice.

"I now need to try and play the rest of the season, to keep going and performing like I did against United and City. That's all I can do."