Fleetwood – promoted via the League Two play-offs last term – have adapted well to life in the third tier and quickly moved to the top of the table.
Consecutive wins against Crewe Alexandra, Notts County and Scunthorpe United mean Alexander's side will be full of confidence ahead of Chesterfield's visit on Saturday.
But Alexander has demanded focus from his players against a side who were promoted as champions last season.
"I was really pleased with our performance [at Scunthorpe on Tuesday]," Alexander told the club's official website.
"I thought we were very professional and looked dangerous when we got forward. But we have to maintain our form - and look to improve.
"There can be no resting on our laurels and thinking we have cracked it after the start we have made."
Chesterfield have also started brightly, winning two of their three fixtures to sit sixth, but they did slump to a 1-0 home defeat against Milton Keynes Dons on Tuesday.
Coventry City will travel to the MK Dons in high spirits after the news this week that they look set to return to the Ricoh Arena for home matches this season.
Coventry have been tenants at Northampton Town's Sixfields Stadium - more than 50 kilometres away from the Ricoh Arena – since last season after an ugly dispute that involved the local council and landlords.
Preston North End, tipped as one of the promotion favourites this term, battle Oldham Athletic in all-Lancashire clash on Saturday.
Simon Grayson's side are one of just five teams still unbeaten in the division and they will fancy their chances of extending that run at Deepdale.
Oldham are winless this season and sit 21st in the table.
Like Fleetwood and Preston, Bradford City and Bristol City are also yet to taste defeat in the new campaign.
Bradford, who sit second, face a potentially difficult test at home to Peterborough United, though, with Darren Ferguson's side also in the top six.
Bristol visit a Rochdale side who, after two losses to start the season, thumped Crewe 5-2 on Tuesday.
At the foot of the table, Scunthorpe and Crewe will be desperate to finally win their first points of the season when they take on Yeovil Town and Swindon Town respectively.
Doncaster Rovers, relegated from the Championship last term, need a win against Colchester United to keep the pace with the top six while Sheffield United will hope to make it back-to-back league wins when they host Crawley Town.
Other matches see Barnsley take on Gillingham, Leyton Orient clash with Walsall and Port Vale play Notts County.
