This time last year, Sunderland were dreaming of promotion to the Premier League after going top of the Championship table by beating Luton Town.

Fast forward 12 months and the Black Cats have just beaten Club World Cup champions Chelsea to move to within two points of leaders Arsenal in the Premier League table.

To describe Sunderland's start merely as a dream would be to do it a disservice.

With 17 points from nine matches, they have not only bucked the recent trend of newly promoted sides struggling in the Premier League but they have defied critics that accused them of making too many signings.

So, how have the Black Cats done it?

To put Sunderland's start into context, it's worth remembering how the Black Cats defied expectations to reach the top-flight again.

Regis le Bris' side finished 24 points behind Burnley and Leeds in the automatic promotion spots and managed just 58 goals in their 46 games.

They required an injury-time winner to edge past Coventry in the play-off semi-finals and they were clear underdogs going into the final at Wembley against Sheffield United, who finished 14 points ahead of the Black Cats.

But Sunderland showed their resilience again, coming from behind in the final and scoring another injury-time winner through Tom Watson to regain top-flight status for the first time in eight years.

It makes this season's start all the more impressive.

The 17 points Sunderland have accumulated from their nine matches so far is the Black Cats' equal best start in the Premier League, matching the tally from the 1999-00 season.

Only five newly promoted teams have earned more points from their opening nine matches than Sunderland have managed this season.

All five of those teams, as well as Sunderland in 2000, managed to survive relegation.

"Anyone who is honest enough will say that they never expected Sunderland to start this well, so full credit to them," Michael Carrick told BBC Radio 5 Live after the win at Chelsea.

"The amount of points they have accumulated already has given them an unbelievable start and that's something they will want to build on.

"They looked quite comfortable and calm for long periods, but also looked dangerous. They just kept that belief to get the win.

"It's a textbook away win at an, arguably, bigger team."

Perhaps the most surprising element of Sunderland's start - beyond their points tally - is that they have managed to embed so many new signings after promotion.

The club spent £161m on 15 new players - a record level of spending for a promoted side.

The season before, the three promoted sides - Leicester, Southampton and Ipswich - spent a combined £276.5m but they returned to the Championship with the lowest combined points total of relegated sides in Premier League history.

Essentially, spending big is no guarantee of survival.

It makes Sunderland's start even more of an outlier, with the Black Cats challenging perceptions about making too many changes to a squad that have earned promotion.

"It's an unbelievable start and one that's been well earned," former Watford captain Troy Deeney told Final Score.

"Most teams when they come up stick with the players that got them up but Sunderland were ruthless.

"They changed the goalkeeper and more or less every single player and said 'we will try and stay up', and to be second in this moment in time, not only will they have belief they can stay up but they'll think, 'do you reckon we can get in the top 10?'.

"If you said that a couple of months ago Sunderland fans would tell you you're crazy."

Signing so many players could have disrupted the harmony of the dressing room, leaving the players that helped the club back into the top flight resenting those that have come in and taken their place.

But, on this evidence so far, it's been the opposite.

"We built our identity through pre-season and before," said Le Bris after the victory at Stamford Bridge.

"The togetherness, the ability to defend and suffer together. We struggled a bit to find the right balance in possession but we were good on the ball, found spaces and tried to press high when possible then in a deep block as in the middle they can punish you.

"We did well and I am really proud of the squad and staff, the starters and finishers because the substitutes were important again. We worked hard and played good football."

The suffering that Le Bris talks about is illustrated by the Black Cats' off-the-ball work.

They have averaged 42.5% possession in their nine matches this season - only Crystal Palace, Everton and West Ham have a lower average.

But, despite spending so much time without the ball, only Arsenal and Manchester City have conceded fewer goals than Sunderland.

That says Le Bris has got his side organised and committed without the ball, and the numbers back it up.

Sunderland's 53.3% duel success is the second best in the division behind Manchester City.

Of Sunderland's summer recruits, none has been more influential than Granit Xhaka.

The former Arsenal captain raised eyebrows when he decided to leave Bayer Leverkusen for the north east in the summer.

There were even question marks whether the 33-year-old could still cut it in the Premier League, having left for Germany in 2023.

But he has confounded the critics in spectacular style.

The Swiss ranks first for assists (three), chances created (11), successful passes (397), passes into the box (49), touches (629), duels won (56) and possession won (43).