So this is what defeat feels like, Kyril.

Sunderland's new owner experienced the first defeat of his two-month reign as the Black Cats' 14-game unbeaten run - a sequence that included 12 league matches - was ended by Charlton Athletic at the Stadium of Light.

Since their last defeat, a 2-1 reverse at Shrewsbury Town in mid-February, Sunderland have transformed themselves from a team on the outside of the top six looking in, to a side pushing for automatic promotion.

And while this defeat is a major setback to their automatic promotion hopes, it should not overshadow all the good work that has gone before.

But while no-one expected Sunderland to remain unbeaten until the end of the season, that was little consolation at full-time.

This defeat came on the back of the Easter Monday draw at Peterborough United, and a return of one point from a possible six has set nerves jangling on Wearside.

While third-placed Sunderland were losing against Charlton, their automatic promotion rivals Hull City and Peterborough both took full advantage as they recorded convincing wins to open up a comfortable points gap.

Sunderland had gone into the weekend knowing that their promotion fate - indeed, the title - was in their own hands, but now they playing catch-up.

Leaders Hull are now eight points clear of Sunderland and second-placed Peterborough five points, albeit the Black Cats have two games in hand of the Tigers and one in hand of the Posh.

And it was not only the big picture that was a concern, it was the manner of the defeat against the Addicks.

Sunderland's injuries were self-inflicted, from the chances they failed to convert, to the two diabolical set-piece goals they shipped.

It all felt so avoidable.

Charlie Wyke, Sunderland's 27-goal leading scorer, passed up a couple of opportunities inside the first 10 minutes that he would have taken without a second thought just a few weeks ago, volleying the first wide and later being denied in a one-on-one by goalkeeper Ben Amos.

Aiden O'Brien, Callum McFadzean, and Wyke again were also frustrated by the superb Amos in the first half.

If Sunderland's finishing was uncharacteristically poor, the same could be said for their defending as they struggled to contain Charlton's counter-attacks and looked especially vulnerable at set-pieces against an Addicks side that had height advantage.

The post came to Luke O'Nien's rescue when he almost glanced a free-kick into his own net.

But the opening goal on the half-hour was a real mess, as Lee Burge stopped but did not hold Ryan Inniss' downward header from a corner, and when Josh Scowen on the goalline attempted to clear the loose ball he somehow contrived to slice it into the roof of the net.

Sunderland had the woodwork to thank again when Jayden Stockley hit the post with a header from close-range just before the hour.

Charlton's second goal a minute or so later was just as sloppy as the first, with Stockley allowed to flick-on a throw-in on the edge of the box, and Lynden Gooch failing to track the run of Alex Gilbey as he burst into the box to collect and prod the ball under Burge.

Scowen pulled a goal back in bizarre circumstances after Amos had made a double save from Wyke and then sub Ross Stewart out near the right-hand corner of the box, with the loose ball falling to the midfielder inside the D and he sent a diving header into the unguarded net.

Sunderland put Charlton under pressure in the final 10 minutes but could not find an equaliser.

The important thing now is how Sunderland respond to this result.

They must not panic.

They must not feel sorry for themselves.

And they must not let doubts creep in.

Instead they must channel their energies into winning at Wigan Athletic on Tuesday, which is their game in hand over Peterborough and one of their games in hand on Hull, to keep the pressure on the top two.

The run-in still has a way to go, and Sunderland found out on Saturday how the promotion situation can change over the course of 90 minutes.

It can swing back in their favour just as quickly.