By Martyn Herman
LONDON (Reuters) - There were plenty of furrowed brows when Maurizio Sarri arrived at Stamford Bridge with minimal fanfare in July, tasked with turning Chelsea back into the Premier League's top dogs.
Five games into the season and with Chelsea top of the table with five wins the Italian, yet to win any silverware as a coach, has already gone a long way to winning over the sceptics.
The contrast with Manuel Pellegrini, the Chilean hired to turn under-achieving West Ham United into a credible force, could hardly be greater.
Despite Pellegrini spending over $125 million in the transfer window, his first four league games ended in defeats and the natives at the London Stadium were already restless.
He snapped that sequence with his side winning 3-1 at Everton last weekend and now he will target Sarri's Chelsea as he seeks a first home victory.
While Pellegrini has struggled to assemble his expensive jigsaw together, Sarri has quietly tweaked Chelsea's style with minimal additions to the squad which served predecessor Antonio Conte well throughout his two seasons in charge.
Of the 11 that started against Cardiff City last weekend, only three were not at Stamford Bridge last season.
While keeper Kepa Arrizabalaga and loanee Mateo Kovacic have slotted in well, it is midfield schemer Jorginho, a loyal servant of Sarri's at Napoli, who has got Chelsea's engine purring so quickly at the start of another new era.
Sarri is not the first Chelsea manager to win his first five Premier League matches in charge - fellow Italian Carlo Ancelotti also managed it in the 2009-2010 season with his side romping to the title with 103 goals scored.
His perfect start will be fully-tested at West Ham, however, after they appeared to turn a corner at Everton.
West Ham defender Pablo Zabaleta, who won the league title at Manchester City with Pellegrini in 2014, said the Blues can expect a feisty London derby.
"Chelsea have a lot of quality but if we play with the same intensity and concentration as we did against Everton, then who knows? Anything can happen, especially at home," he said.
"Against Everton, we needed to react. We did and we proved to ourselves we have a chance to win games if we play this way."
Second-placed Liverpool, the other club to start with five wins, will be confident of making it a six at home to Southampton, especially with confidence at sky high levels after Tuesday's 3-2 win over Paris St Germain in the Champions League.
Third-placed Manchester City travel to Cardiff City on Saturday while Manchester United seek to maintain their improved Premier League form at home to Wolverhampton Wanderers.
Tottenham Hotspur's early-season optimism has been buried by three consecutive defeats in all competitions -- the first time they have suffered such a run under Mauricio Pochettino.
They will be eager to get back on the rails away to Brighton and Hove Albion.
North London rivals Arsenal, who started the Unai Emery era with two defeats but have now won three in a row, host Everton on Sunday.
Four clubs, Cardiff, Huddersfield Town, Newcastle United and Burnley, are seeking their first wins of the season.
Huddersfield go to Leicester City, Newcastle to Crystal Palace and bottom club Burnley host high-flying Bournemouth.
(Reporting by Martyn Herman, editing by Pritha Sarkar)