Vincent Kompany believes standards have been driven up at Manchester City by increased competition for places.
City have started the season in blistering fashion, winning their opening three Barclays Premier League games without conceding a goal and scoring eight.
After a frustrating 2014-15 campaign, the squad was bolstered over the summer, chiefly with the signings of Raheem Sterling and Fabian Delph.
And, despite the impressive results since, City are still recruiting. They spent £32million to sign defender Nicolas Otamendi from Valencia last week and continue to be heavily linked with Wolfsburg playmaker Kevin de Bruyne.
City captain Kompany said: "That is one of the reasons we have started so strongly.
"You can't really afford to do anything wrong during the week leading up to the game. Then, during the game, you can't do anything wrong either as there is always someone looking over your shoulder, waiting, who is just as good as you.
"If they are in a better moment and they deserve a chance, they will take your place. You have got to be at the top of your game. This is what you are seeing - a group of guys who know that they need to perform. If they don't, someone else will do it."
Kompany's team-mate Jesus Navas agrees and has warned that City are determined not to let standards slip.
The winger said: "It is not only that we have won these three games, it is that we didn't concede any goals and we created a lot of chances. We are really happy.
"It was a very important win against Everton and also two really nice goals. We worked really hard in training and luckily we got the three points. This is what we wanted.
"We need to keep the same attitude, working really well defensively and also creating a lot of chances."
Kompany, 29, is likely to be feeling the competition as keenly as anyone.
The Belgium skipper fell below his own high standards last season and consequently reported back early for pre-season training.
His performances have suggested he is back to his best, but with Otamendi arriving to boost central defensive ranks that also include Eliaquim Mangala and Martin Demichelis, he cannot ease off.
He said: "It shows on the pitch that I feel good and I feel happy with myself. I just don't want to miss any opportunities to have a good game or have a good season. Every game counts for me.
"The extra competition is good. You don't play for a top team unless you have that."
City's defensive solidity so far this season is a source of great satisfaction for Kompany.
He added: "Not conceding is as equally as important as the goals we score."