The suspicion that Luke Moore's rising star is on a temporary wane solidified yesterday as manager David O'Leary called on the Aston Villa striker to become more clinical in front of goal.

Moore is his club's second-leading scorer - with eight this season, he trails Milan Baros by one despite having started six fewer games - but was taken off after an hour of last Sunday's FA Cup fifth-round 1-1 draw with Manchester City after a quiet performance.

The 20-year-old's display was a stark contrast to the recent goalscoring sequence of five in three Premiership games, which had made him the only Villa forward in good form.

An equaliser at home to Chelsea was followed by an amazing hat-trick at Middlesbrough as Moore gave the Irishman serious selection problems for the visit of Newcastle United earlier this month.

O'Leary decided to use the youngster ahead of Juan Pablo Angel and Milan Baros for that match and, despite watching his team go down 2-1, was rewarded with yet another strike. All seemed to be going well until Moore failed to make an impact in the FA Cup tie with the Mancunians.

As a result, O'Leary has told the Birmingham-born player that he must make the most of the opportunities he receives and do so over an extended period of time before he can be considered the finished article.

"He has got potential," O'Leary said. "But he's still got a long way to go. What he has got to do and improve on is that when he gets chances, he has to put them away, like he did at Middlesbrough.

"He has got to score more goals. His ratio of goals has got to go up, it's good at present but he will not be judged over a few games, he will be judged on whether he can do it repeatedly."

For O'Leary, who made his debut for Arsenal as a 17-year-old, age is no excuse.

"I don't care if he is a young lad," he said. "Whoever it is, if they do the business they stay in the team. It is up to him how long he stays in the team."

Whether he can do that for Saturday's match with Charlton Athletic remains to be seen.

Baros fired the Villa goal as they went ahead against City, Angel replaced Moore while Kevin Phillips stayed on the bench. A return to O'Leary's preferred Czech-Colombian axis at The Valley has to be considered likely.

For his part, goalkeeper Thomas Sorensen has called on supporters to give Moore time to realise his undoubted potential. "He's a young kid in great form, but you can't put too much pressure on his shoulders," the Dane said.

"I just hope he can keep up his current level of performance as it certainly makes for good competition with four strikers to choose from."

Moore will get another chance to impress against City in the fifth-round replay which will take place on either March 14 or 15.

The tie had originally been pencilled in for March 8 but, with only two draws among the eight fifth-round matches, the game will been shown live on television.

Broadcasters are eager to avoid a clash with key Champions' League and Uefa Cup ties the previous week, so have opted to push back the Eastlands encounter.

The winners will, therefore, have little time to prepare for their sixth-round meeting with either Bolton or West Ham which has been scheduled for the following week - probably on Monday March 20.

Meanwhile, midfielder Mathieu Berson, on loan with Auxerre, looks likely to make the move permanent in the summer on a £500,000 fee.