The Black Cats eased to a 3-0 win over Blackburn Rovers on Saturday to go sixth in the table, but, rocked by the news that captain Lee Cattermole is to miss the next month with a back injury, Bruce is concerned that his young squad may not be able to sustain an assault on the top half of the Premier League.
Echoing a belief long held by his former mentor Sir Alex Ferguson at Manchester United, Bruce - who again played down talk of European qualification - said: "The league starts to sort itself out about now. It starts now, and we have given ourselves a chance.
"Question is, can we maintain it Cattermole is out for a month with a back injury. So that is a blow. We have been advised to rest him. We have Mensah and Turner out too, but we have a nucleus of a good young squad.
"I will talk about establishing in the Premier League and not be a yo-yo team, like Sunderland have been in the past. But I'm not here to talk about Europe.
"It is nice to see we are sixth, but it's nicer to have 33 points which we should have. I have good young players who I enjoy working with. I knew I was losing players when I was sixth with Wigan. Here, we don't have to lose anyone - and that's very pleasing.
Injuries to Cattermole, Turner, Onuoha - who will miss another fortnight - have caused problems for Sunderland, but, that said, they eased to their tenth clean sheet of the season against Rovers.
Such an achievement, Bruce believes, is testament to his squad, who are on average the youngest in the Premier League.
Bruce reserved special praise for Jordan Henderson and David Meyler, who played his first full match in seven months after a cruciate ligament injury.
He said: "When you look at Cattermole as well, he is 22, Elmohamady is 22. I am delighted for David Meyler. Jordan (Henderson) gets the headlines, but David has done everything to get back playing again.
"The two of them have a wonderful appetite. No one will work harder and be more committed than them two. Energy, honesty, endeavour.
"He does all the things a team needs. You have to win the ball back. We all like footballers but he does the ugly side well and to play against him must be a nightmare. He is up and down the pitch. Look at Gyan's goal, David was up there haring alongside him in the 89th minute."
Bruce dedicated the win to former Rovers manager Sam Allardyce, a close friend of the Black Cats manager who was fired by Rovers' new owners Venky's - a decision which Bruce branded 'ludicrous'.
"That is for Sam," Bruce declared. "For the nonsense that went around for his sacking. I hope he has a drink in Dubai where he is today. He is a pal.
"But the ludicrous situation they have put themselves in to sack him and appoint his coach is ridiculous. Winning today is a good result for football."
"I am not saying Steve (Kean) was responisble. The people who sacked Sam were responsible. I have had a drink with Steve."
Meanwhile, Bruce was delighted that Darren Bent ended his barren spell with a 19th minute goal.
He said: "I have never lost faith in Darren. I have been fortunate to have played with great strikers. That all go through a little bit of it.
"The good thing for Benty is that he never shied away from it. He will always come back for more. He has that mentality of 'If I miss one I will get the next'. He has got it today. He is the top English scorer in the calendar year. That is a remarkable achievement.
"Yes he has not scored in December. Wow. He will be OK. For me class in permanent and Darren will always score a goal. Always has done."