After his side's 24-10 defeat to Harlequins, Diamond was in combative mood after suggestions that he had selected the team on the premise that they would meet EQP requirements.
"England are hosting the World Cup in 2015. Up here, we're proud of players who want to play for England and we've got a lot of ambition," he said. "Today was a wonderful chance for our lads who have played quite a lot of games this year, but been in the shadows as well, to play in the first team in front of a full house against a top side."
The chief executive then went on to slam Premier Rugby, referee Martin Fox and the way in which the body select officials for each match.
He added: "I think we were accused earlier on in the week of fielding a weakened side by Premier Rugby. I think Premier Rugby should take the bigger issues of avoidance of salary caps by some clubs.
"A refereeing decision in the first two minutes went against us which was the wrong decision.
"We picked our strongest side, contrary to what Premier Rugby and various other people have accused us of doing. To put 23 English players out in one game is remarkable; I think we should be applauded for it.
"We work within the guidelines we're told, I think it's 14 per game and, at the end of the season, you've got to make sure that tally adds up.
"If Premier Rugby wants to look at my team selection, I think they should look at their referees' selection and the standards of that area.
"Two or three crucial decisions went against us today which would have won us the game. They ask you to hit the quota, we've done it and with due respect, we get our money and that's the way business runs. Job done."