John Terry's confident claim that Chelsea have emerged from the summer break stronger than their top four rivals will be severely tested at Sunderland.
Blues skipper Terry has spoken confidently about the club's title chances this season after seeing the Premier League's other leading teams lose key players while Carlo Ancelotti's squad has remained largely untouched.
Stability, Terry believes, can be the key in the coming months.
But his assertion looked less than convincing during a stuttering opening day performance against a Hull City side widely tipped as one of the favourites to go down.
Didier Drogba proved the difference in that game with the Ivorian's two goals confirming his importance to Ancelotti's plans of forging a title-winning side in his first season since arriving at Stamford Bridge from Milan.
And his match-winning display suggested that Chelsea's success in securing the forward's future with a new, three-year contract could be their best piece of business of the close-season break - better even than convincing Terry he should reject the overtures of Manchester City and stay at the club.
Florent Malouda and John Mikel Obi have also agreed new deals with England left-back Ashley Cole set to follow.
The squad now looks unlikely to be bolstered by the major signing the club promised ahead of the current transfer window, particularly in the light of Franck Ribery's determination to remain at Bayern Munich despite interest from Chelsea, Real Madrid, Barcelona and Manchester United.
"I can't stop clubs making offers," said the France international.
"What I can tell them is today I am still at Bayern. That door was well and truly closed. My bosses really want me to stay."
Drogba's added-time winner against Hull suggested there is nothing wrong with Chelsea's spirit, but the overall display was flawed and against a better team, they would have been fortunate to collect three points.
Ancelotti's decision to replace Mikel at half-time with Michael Ballack was an admission that his midfield hadn't gelled and the German international will almost certainly start at the Stadium of Light against Steve Bruce's re-shaped Sunderland.
Their opening day victory at Bolton confirmed that this year's Sunderland is a very different model to the one that flirted with relegation during a dismal campaign last season.
Bruce's decision to spend £10 million on Tottenham striker Darren Bent brought immediate reward when the England international headed the winner at the Reebok Stadium and the acquisition of Lee Cattermole had added steel to a previously flimsy midfield.
Lorik Cana, the Albania international, fitted in well alongside Cattermole but with Steed Malbranque and Kieran Richardson both struggling for fitness ahead of the visit of Chelsea, Bruce's side may lack invention and creativity in the final third.
"I've had a couple of good tussles with Chelsea from my Charlton and Tottenham days and I've scored a couple of goals against them," said Bent.
"They are one of the best teams in the world and we will have to work doubly hard to get something from the game. But the way we played against Bolton showed we can match anyone."
Fixtures
Today: 20.45 Sunderland vs Chelsea; Wigan vs Wolves.
Tomorrow: 20.45 Birmingham vs Portsmouth; Burnley vs Man. United; Hull City vs Tottenham. 21.00 Liverpool vs Stoke City.