Davies initially thought his England inclusion was a wind-up

Gabriel Agbonlahor, Gareth Barry, Scott Carson, Curtis Davies and Ashley Young all feature in the 30-man squad.

"They have been absolutely terrific, I'm delighted - just to be in the manager's thoughts is absolutely fantastic for them," said O'Neill.

"It's a great credit to the players and also reflects well on the club."

Interview: Aston Villa boss Martin O'Neill

It is the first time Agbonlahor, Young and Davies have featured in a full England squad.

Although David Beckham's omission dominated the headlines, it was Davies's inclusion that has caused the most intrigue.

The 22-year-old defender - currently on loan from midland rivals West Brom - compared his debut Villa performance in the League Cup defeat to Leicester in September with a pub player.

606: DEBATE It's a great achievement for the players and well done to Capello for recognising Davies's ability and potential Al_Kidda

But O'Neill said Davies's honest assessment exemplified the high standards he sets for himself.

"He didn't play particularly well - but he wasn't the only one that evening," the former Celtic manager told BBC Radio 5 Live.

"He was very harsh on himself and that's one of the endearing qualities about Curtis, he does analyse his game.

"He has made massive strides since then. He got his opportunity when Zat Knight was sent off against Chelsea on Boxing Day.

"And he has taken his chance and come from relative obscurity to take his place."

O'Neill has guided Villa to fifth place in the Premier League despite having the smallest squad of players in the top flight.