Manchester (United Kingdom) (AFP) - Manchester City manager Pep Guardiola said the door was not closed for club stalwarts like Joe Hart and Yaya Toure despite dropping them for his first Premier League game.
France internationals Eliaquim Mangala and Samir Nasri, meanwhile, were omitted from the squad for City's Champions League play-off match at Steaua Bucharest on Tuesday, the latter over concerns about his weight.
But Guardiola said: "I don't have any complaints about these names. Yaya trained really, really good.
"Sami arrived a little bit... but the last one week, two weeks, he's training amazing, so I'm really impressed about the quality of Sami.
"Mangala, you know better than me how professional he is. But at the end I have a squad and I decide what I see. I have to create a team spirit. It's not about tactics.
"I decide for this line-up today. That doesn't mean in the future they are not going to play. In Barcelona, in (Bayern) Munich, it was difficult to repeat a line-up.
"I'm a guy so I take decisions. I'm not afraid about that. What I feel, I do it. Today in the world, people are afraid to take decisions. I like to take (them).
"It's not that Joe cannot play or Yaya or Sami or Mangala. But today I decide for that, for many reasons."
Guardiola is reported to be interested in signing German goalkeeper Marc-Andre ter Stegen from Barcelona.
But he said the decision to bench Hart was purely down to the fact Caballero had spent more time working on build-up play with centre-backs John Stones, who made his debut, and Aleksandar Kolarov.
City prevailed courtesy of an 87th-minute own goal by Sunderland debutant Paddy McNair, who had only been on the pitch for four minutes.
Sergio Aguero put City ahead with an early penalty, but the hosts failed to make their dominance count and Jermain Defoe equalised with 19 minutes remaining.
- 'Gut-wrenching' -
Asked what he had learnt about the Premier League, Guardiola said: "I realise how difficult it is, definitely.
"We are not safe until the referee says, 'OK, go home.' Long ball, free-kick, long ball, throw-in, ball in the box, tall guy, second ball...
"I can imagine the last five minutes in an away game. That's why you have to create more chances."
David Moyes, who was taking charge of Sunderland for the first time in a competitive match, described the outcome as "gut-wrenching".
Sunderland's defence was impressively marshalled by Ivorian centre-back Lamine Kone, who was the subject of an unsuccessful bid from Everton.
He reportedly tabled a transfer request earlier this week, but Moyes said that Kone had no knowledge of a statement that had been attributed to him by British media.
"I expect him to stay. Strangely enough, when I pulled the boy (aside) yesterday, he didn't know anything about his statement," Moyes said.
"The boy was great. He was great today, he was great yesterday. We've told him that on September 1, we'll look to do a contract if that was what was said.
"We also told him that we've had an offer from Everton as well. So we've not hidden everything."
Despite the result, Moyes took heart from his team's doggedness and urged his players to build on the momentum they generated during their escape from relegation last season under his predecessor, Sam Allardyce.
"We need to play at that level of intensity. But I want us to have more of the ball," said the former Manchester United manager.
"I want us to give the crowd something to shout about. But more importantly, I need to build on what happened last year with Sam. They avoided relegation, we've now got to keep the momentum going."