This was supposed to be a day of celebration, the Stadium of Light marking its 20-year anniversary with a showpiece friendly against Scottish Champions Celtic.
Instead, Simon Grayson's side were thumped 5-0. Thoroughly outclassed as Celtic ran riot in front of thousands of their own supporters.
Callum McGregor bagged a hat-trick for Celtic, Wahbi Khazri went off with a knock, Lamine Kone was poor, Jason Steele endured a debut to forget. Sunderland struggled all over the pitch.
This was a massive wake-up call for Sunderland with the Championship campaign kicking off against Derby County on Friday night.
There is a huge amount of work to be done between now and then.
Grayson named a strong starting line-up with all six of his new signings making their Stadium of Light debuts. There was no Robbin Ruiter though, the free agent had starred in the previous two games on trial but there is interest from elsewhere including Burnley, to cast doubt over his future.
Josh Maja and Jeremain Lens - the subject of a failed bid from Besiktas on Friday - who both missed the goalless draw at Scunthorpe with injury were again missing.
This wasn't even Celtic's strongest side, Scottish treble-winners’ Celtic made six changes from their UEFA Champions League game midweek qualifier with Rosenborg.
Sunderland matched Celtic's 4-2-3-1 formation, with Vaughan leading the line with Grabban wide right, McGeady wide left and Khazri in the No.10 role.
Celtic took an early lead after a defensive howler from Sunderland. Tyias Browning played the ball back to Steele in his area, his rushed pass to Lamine Kone was poor but the defender's clearance was horrendously miscued - only succeeding in laying the ball off to Callum McGregor who slid the ball past the club's new No.1.
There was a moving minute's applause from both sets of supporters in the sixth minute in honour of Bradley Lowery - with fans joining in a rendition of 'There's only one Bradley Lowery.'
Sunderland looked to hit back straight away. McGeady, who started his career at Celtic jinked his way into the box before providing a delicate cross for Vaughan. The ex-Bury striker got a firm connection with his header but Dorus de Vries produced a stunning save to push the ball away.
It was soon 2-0. Sunderland cut apart defensively in the 14th minute with Kone again caught out as McGregor slid the ball past Steele to add his and Celtic's second.
Khazri was quick to capitalise on a Celtic defensive error 25 minutes in but he couldn't convert the chance, with the Hoops recovering despite appeals for a penalty.
Khazri picked up a knock in the challenge and was subbed on the half hour mark with George Honeyman on.
McGregor was inches away from bagging his hat-trick 29 minutes in, his low effort beating Steele but rebounding off the post.
Earlier, Sunderland's £500,000 signing from Blackburn Rovers endured a nervy few moments after coming quickly off his line but failing to deal with the danger. A goalline clearance form Galloway spared Steele's blushes.
It was all action and Sunderland won a penalty after Grabban played in Honeyman who was then fouled by Oliver Ntcham.
Vaughan stepped up but his low effort was saved by De Vries down to his right, the stirker failed to convert the follow-up too. A poor effort. His second penalty miss of pre-season.
Celtic made it 3-0 almost immediately. Steele parried away Ntcham's initial drive, Galloway failed to close down Jonny Hayes and he tucked the ball into the corner.
Sunderland, with thousands of empty seats in the home end, had been outclassed.
Half-time: Sunderland 0 Celtic 3
There was nothing of note in the opening 10 minutes of the second half, Billy Jones doing his best to spark the game into life with a mazy run beating two players.
Kone, who had started the second half in the same fashion as the first, was subbed after just 54 minutes. John O'Shea on in his place. Kone had endured a nightmare afternoon.
Sunderland's misery continued as Celtic made it 4-0 from the spot. McGregor sending Steele the wrong way in the 55th minute to complete his hat-trick after Galloway fouled Tony Ralston.
It soon got worse, 20 minutes before the end. Nir Bitton rolled a free-kick to fellow sub Stuart Armstrong and he had acres of space to pick his spot from distance. Sunderland failed to close him down, while Steele would again have been disappointed. It was embarrassing stuff at the Stadium of Light and sadly no cause for celebration on the 20-year anniversary of the stadium opening.
Full-time: Sunderland 0 Celtic 5
Sunderland: Steele, Jones (Matthews, 77), Galloway, Kone (O'Shea, 54), Browning, Cattermole (C) (Gibson, 77), Ndong, McGeady, Grabban (Asoro, 67), Khazri (Honeyman, 30), Vaughan.
Subs Not Used: Mika, Stryjek, Love, Embleton, Djilobodji.
Celtic (4-2-3-1): de Vries, Ralston, Ajer (McCart, 75), Tierney (C) (Hill, 66) , Miller (Benyu 75), Kouassi (Aitchison, 88), Ntcham (Bitton, 52), Hayes (Rogic, 66), McGregor, Sinclair (Armstrong, 66), Forrest (Ciftci, 66).
Subs Not Used: Gordon, Hazard, Henderson.
Goals: McGregor (5, 14, 55), Hayes (39), Armstrong (70)
Referee: Tony Harrington