The away side feel they could have won the game long before the sending off. They had a number of great chances in the first half to take the lead.
Story of the match
Sunderland took the lion share of possession and the majority of the chances in the first half. After starting slowly against Peterborough last week, Phil Parkinson's men knew that a confident start was needed against a strong Charlton side.
After a scrappy first ten minutes of both sides battling for possession, the away side began to assert their dominance.
Danny Graham was the main man in the opening 45 - perhaps for the wrong reasons. The 35-year-old forward has three big opportunities to put his side into the lead.
Halfway through the first half, Luke O'Nien beat Ben Purrington and whipped in an out-swinging cross from the right-hand side. The ball landed awkwardly by Graham, but he couldn't get a meaningful touch on it, forcing a comfortable save from Ben Amos.
Shortly after, Bailey Wright had a chance as he met Josh Scowen's corner from the right. The Australian thumped his header on target and only a brilliant save from Amos once again.
Sunderland had a lot of joy down the right-wing throughout the half, with Willis, Scowen and O'Nien linking up well. This led to Sunderland's, and Graham's, biggest chance of the half.
Scowen skipped away from Purrington and fizzed in a cross that Aiden O'Brien missed. The ball found its way to Graham around six yards out, but he could only fire his effort over.
Lee Bowyer will have been extremely disappointed with his side's first-half display as they struggled to create anything. Lone striker Connor Washington was isolated whilst his teammates played long balls, that Sunderland's back three were comfortable dealing with.
When the away side did manage to keep the ball for long periods of time, they did manage to create an opportunity at the end of it. The defence remained as solid as usual, perhaps injecting confidence throughout the team to express themselves.
The second half began as scrappily as the first did, but Charlton moved the ball with a bit more purpose.
Manchester United loanee Dylan Levitt had their first shot on goal on 48 minutes with a long-range effort. Bowyer's men started to get more bodies up the pitch early on in the second half.
At the other end, Lynden Gooch and Scowen had long-range half-chances, but neither tested Amos in the Charlton goal.
Both sides struggled, in general, to stamp their authority in the second half. Charlton enjoyed more possession but failed to seriously worry Lee Burge.
The introduction of Johnny Williams aided their efforts; his dribbling and vision helped his side move further up the pitch. Again, he couldn't really create any big chances for most parts.
The game took a huge turn on 73 when Sunderland defender Tom Flanagan was sent off for a professional foul.
Flanagan brought down Connor Washington before being through on goal after a smart flick-on from substitute Chuks Aneke.
After being so comfortable all afternoon, Phil Parkinson will be extremely disappointed that one of his defensive stalwarts was so reckless.
This turned the game on its head as Charlton took the ascendency. Sunderland switched to a back four and the defensive line dropped five yards back, allowing the home side to come forward.
Charlton earned more chances as time ticked on. With five minutes remaining a Marcus Maddison free-kick was met by Aneke looking to flick the ball across goal.
Sunderland defender Jordan Willis heroically cleared the ball just before Ben Watson could meet it to finish.
Sunderland need to get their forward players firing
Sunderland must get their forwards firing. Danny Graham's efforts cannot be faulted, however, his finishing this afternoon must come under scrutiny. Similarly, with Aiden O'Brien, his work rate is impeccable, but he lacks that quality in the final third and often gets dragged out wide.
Sunderland's creativity in the first half should have reaped rewards. O'Brien simply failed to make an impact and tended to miss the ball when crosses came in. Graham managed to get on the end of the crosses but his finishing was simply woeful.
Both starting strikers were hooked for Charlie Wyke and Will Grigg. Wyke had an opportunity to tap in after a pullback from Denver Hume. Wyke didn't make a connection and squandered the chance.
If Sunderland took their chances in the first half, the sending off may not have affected their nerves, stopping Charlton from coming forward.
Phil Parkinson must be worried that his striking options are yet to score prolifically this season. The Sunderland boss will want to see vast improvements in these areas if they are to achieve promotion.
A dogged performance from the Addicks
Lee Bowyer will be pleased that, though they were poor in the first half, they managed to hold on. They were then slightly the better side in the second period.
Experienced players in the Charlton side like Ben Watson and Darren Pratley were influential in the side digging deep to stay in the game at times. The two 35-year olds will be massive for Lee Bowyer as Charlton look to bounce back to the second tier.
By the standards of their dogged performance today, Charlton will scrape more points than they perhaps deserve at times.