David Moyes urged patience as he will need time to turn around Sunderland's fortunes following a season-opening defeat at Manchester City.
The new manager seemed to be in a good position for a credible point in his first game in charge after Jermain Defoe's 71st-minute equaliser, but City retook the lead with just two minutes to play as Jesus Navas' low cross led to a Paddy McNair own goal.
Moyes told BT Sport that he thought the Black Cats were worthy of a draw.
"We tried to stifle the game and for long periods we were successful in doing that. I'm just disappointed," he said.
"It was disappointing that we backed off Jesus Navas and allowed the ball to be played across the six-yard box. From there it was always going to be difficult to avoid a goal or an own goal.
"I can't be critical of the players because they did a great job all-round really, but I am disappointed we didn't get a point"
Sunderland barely escaped relegation last season and Moyes said it would not be an instant return to form.
"We are not ready yet. We're not going to be for a while, I've told the players that today," the former Everton and Manchester United boss said.
"I want them to build on how they finished last season, but I want to do better than that. Which can't be done in two weeks."
Moyes gave new signing Donald Love and American Lynden Gooch their first starts in the Premier League, and said the young players would be key for the club this season.
"We are definitely looking short in several areas and will do everything we can to improve the team. But today we gave two young boys their debuts, at Man City," he said.
"So if the young players do well enough we are happy to promote them too."
Lamine Kone impressed for Sunderland despite reports he wanted to quit the club. Everton have made an offer for the 27-year-old and a statement was released under his name on Friday stating he had asked to leave.
Moyes claimed the defender knew nothing about it and believes he will remain at the Stadium of Light.
"I expect him to stay," Moyes said. "Strangely enough when I pulled the boy yesterday he didn't know anything about his statement. He didn't know much about it at all but it was said and his name was put to it. The boy was great, he was great today, he was great yesterday.
"We've told him on Sept. 1 we will look to do a contract and also we've also had an offer from Everton. We've not hidden anything."
Information from Press Association was used in this report.