Sixty-six days have passed since Chelsea supporters started to sing "we've got our Chelsea back" as the Blues breezed past Southampton in the Premier League. Sixty-six days. That is all.

Just over two months have been and gone — yet it feels an eternity to go. In football days, 66 is quite a lot. A lot can happen, and has happened since the Blues put the Saints to the sword. "We've got our Chelsea back" may have felt a bit soon to some but these fans, who have been deprived of such feeling in recent seasons, were starting to fall in love with their players once again. And, crucially, the manager.

Chelsea were up to second in the Premier League table on that cold night down on the south coast back at the beginning of December. Fast forward just over two months and it was another bitter evening on the southern shores of England. The defeat in the FA Cup fourth round at Brighton, however, has left an extremely sour feeling; one that could not contrast any more from the feeling coming out of St. Mary's earlier in the season.

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Since beating Brentford on December 15, the west Londoners have won four matches in all competitions — and two of them came against Shamrock Rovers and Morecambe, who - with no disrespect intended - are nowhere near the Blues' level. A lack of goal scoring prowess has cost Chelsea in that period and an overreliance on Nicolas Jackson, still only 23-years-old, has seen a huge dip in form from the Senegalese striker - who incidentally, missed the defeat at the Amex Stadium due to a muscular injury.

Jackson pulled up in the first-half of the win over West Ham United on Monday night and tried to shake the injury off. However, he was taken off not too long into the second-half with Enzo Maresca not wanting to aggravate the issue at all. Marc Guiu, still a teenager, replaced Jackson and in stoppage time, the Spaniard too pulled up with a muscular problem.

Guiu's injury is thought to be a long-term one and Jackson's minor but either way, Chelsea were left extremely short of options on Saturday night in Brighton. Christopher Nkunku led the line for the Blues and among the substitutes were Noni Madueke and Tyrique George but that was that in terms of attacking options for Maresca. And crucially, neither Madueke or George are strikers.

Nkunku himself is not a natural No.9 either. The Frenchman is much more effective playing in between the lines as a No.10 but Cole Palmer hogs that position for Chelsea - and rightly so because of his brilliance. With just one touch in the opposition box throughout the 90-plus minutes Nkunku played, it is clear Chelsea are severely lacking in that department.

"Sometimes I think you need to play games without players to realise how important they are," Maresca said when asked about how much his team missed the presence of Jackson at the Amex. "We said many times about Nico: he is important on and off the ball. Off the ball, his intensity is very good and on the ball, he is always a threat."

There were times during the game where Nkunku would feel obliged to drop so deep that he found himself collecting the ball from the centre-backs. While Maresca's way of playing is possession-based and looking to patiently build up the attack, this cannot be what the No.9 does. Jackson drops deep but usually to try and bring the centre-backs with him, whereas the Brighton defenders were more than happy for Nkunku to retreat to the halfway line at times.

It is increasingly difficult to criticise Nkunku too much, however, because Chelsea have dug themselves into this position. The failure to recruit a centre-forward over the recently-concluded January transfer window seems to be costing them this season. The UEFA Conference League is now the club's only chance of winning a trophy this term.

Chelsea could not have accounted for the fact that Jackson and Guiu both got injured on deadline day, granted. That is bad luck. It was already apparent, though, that Maresca needed another striker. The form of Jackson had dropped so much and while it can be put down to many things, the reliance on the striker is so strong and when it does not work, there are not many options for Maresca.

Not only that either but no recruitment in midfield has left supporters baffled. Andrey Santos is thriving on loan at Strasbourg and could have been recalled, likewise with Lesley Ugochukwu at Southampton. Mathis Amougou was brought in for £12million but Maresca explained on Friday that the 19-year-old central midfielder was one for the future rather than the present.

There was frustration and concerns going into the January transfer window from Chelsea supporters but the lack of movement on the incoming front has really disappointed those that love the club. They believe it will - and has already - cost the Blues this season. "We've got our Chelsea back" seems a long, long time ago now.