Less than four months on from losing the Champions League final, Mauricio Pochettino's Tottenham saw another chance at a trophy disappear on Tuesday evening in the more humble surroundings of Colchester United as the fourth-tier side progressed to the last 16 of the League Cup on penalties after a 0-0 draw.

Despite resting Harry Kane, Pochettino had every reason to believe a team that ended the game with Dele Alli, Christian Eriksen, Lucas Moura, Erik Lamela and Son Heung-min on the field should have enough firepower to break down a side that sits 10th in League Two, 70 places below Spurs in the English football ladder.

Now into his sixth season at Spurs, Pochettino is still yet to win a trophy in his managerial career and there are growing signs that the huge progress made under his stewardship has stalled.

Tottenham have now won just four of their past 17 games in all competitions and are already 10 points off Premier League leaders Liverpool just six games into the new campaign.

After the difficulties of playing at a temporary home in Wembley with a stretched squad for most of the past two years, this season was meant to signal a fresh start.

The club's sparkling new stadium opened in April and Pochettino has been able to add to his squad for the first time in 18 months with the signings of Tanguy Ndombele, Giovani lo Celso and Ryan Sessegnon.

However, all three have struggled with injuries and the Argentine believes there is a hangover from a summer of uncertainty over the futures of a host of first-team regulars.

Eriksen spoke publicly of his desire to leave at the end of last season and the Dane, along with Jan Vertonghen, Toby Alderweireld and Danny Rose have entered the final year of their contracts.

"When you have an unsettled squad always it's difficult and you lose time and then you need time to recover the time you lose," said Pochettino.

"That's where we are. Maybe our performances are good but you need this extra, which is mental, a connection, it's energy to be all together, not to have different agendas in the squad.

"We need time again to build that togetherness that you need when you are competing at this level."

Pochettino is not looking at a quick fix and is already eyeing up the next two transfer windows to refresh a group that appears to have grown stale.

"January is going to be a good opportunity to try and fix this type of situation and sort it," said Pochettino.

"Then the next transfer window, again. To keep the successful period in football you need to be different every single season and act differently and find different solution.

"Maybe we need to do something different."

Spurs can be grateful that traditional 'top six' rivals Arsenal, Chelsea and Manchester United have also suffered early season struggles, which means they are just three points off the top four ahead of kind run of Premier League fixtures, starting with the visit of Southampton on Saturday.

But after four seasons of Champions League football, a top-four finish is no longer enough to satisfy Spurs' ambitions.

"Starting my sixth season I need to lift a trophy," said Pochettino before the season started.

But with Liverpool and Manchester City again running away in the Premier League title race, that leaves winning the FA Cup for the first time in 29 years or a return to the Champions League final as the only realistic options.