Chelsea: Liam Rosenior's side enter defining run of games, starting with Arsenal away in race for top-five finish

Now it gets serious.

Liam Rosenior made a positive start to his time at Chelsea. There were routine wins against Brentford, Pafos, Crystal Palace and Wolves, and more thrilling ones away at Napoli and in salvaging three points at home to West Ham.

The defeats to Arsenal in both legs of the Carabao Cup semi-final were frustrating, a missed opportunity, but understandable.

But blowing winning positions at home to Leeds and Burnley to draw their past two Premier League home games has shifted the situation.

Chelsea now face a daunting run of fixtures. The toughest run-in of any side competing for Champions League qualification.

After they "set fire to four points from two home games," as Rosenior described it, the pressure is well and truly on.

A top-five finish is far from certain now.

Currently, Chelsea only sit above Liverpool on goal difference. And now they must protect that advantage through a run of games which begins with away days at Arsenal and Aston Villa, and will see Chelsea host Manchester City and Manchester United back-to-back in mid-April.

They then have to go to Anfield on May 9.

And that's before factoring in a Champions League knockout tie against either Paris Saint-Germain or Newcastle, and an FA Cup run, where they have drawn Wrexham, which will reduce training time and put strain on resources.

It is this run of games which weighs into an Opta prediction model that expects Chelsea to finish sixth. That would be a serious step back after Enzo Maresca managed fourth last season and the loss of Champions League revenue would complicate plans for the summer transfer market.

It would also be a finish which would add to the criticism of the squad-building at Chelsea, where a focus on youth and potential over experience has exposed them to suggestions they lack composure and cutting-edge.

After Chelsea's draw with Burnley, Rosenior and opposition boss Scott Parker talked up the quality of the Blues' squad. They rank third in Opta's expected points (xG) table, based on expected goals data.

In fact, they have created a higher xG score than any other side in the Premier League.

But they also rank fourth-worst for underperforming in that metric, having scored around four goals fewer than they should have.

This is a Chelsea team which tops the stats for PPDA (opposition Passes Per Defence Action), a metric which measures how quickly a team wins the ball back. Yet, they have let in 12 set-piece goals. Only four teams have conceded more.

In both boxes, they have been found wanting at key moments.

For Chelsea supporters, this again has been a season of promise and glimpses of what this talented young group can become - but also a season of untimely setbacks, slip-ups and switch-offs which have cost the team at crucial times.

Now, the margin for error is minimal. Now it gets serious.

Chelsea began February with defeat at Arsenal. They will begin March there, hoping to have learnt lessons from that Carabao Cup semi-final second leg loss…

For this Premier League trip Chelsea cannot be gung-ho - but Rosenior will also not want to see a repeat of the slow possession which featured in last week's draw to Burnley. Chelsea were cruising but never got the second goal and Wesley Fofana's red card changed the game.

"I want incision. I want us to create wave after wave of attack," said Rosenior after that draw. He won't get dominance like that at the Emirates but, in possession, Chelsea must show intent.

Rosenior had flooded the pitch with giants when Chelsea went down to 10, aware of Ward-Prowse's quality deliveries. But was left fuming at a player "who didn't do their job" and left Flemming free.

Against Arsenal, the top set-piece scorers in the Premier League, who also scored from a corner against Chelsea at Stamford Bridge, there can be no repeat.

Let's not forget, this is must-win for Arsenal, too, as they look to bolster their Premier League title bid. Emotions will be running high and Chelsea need to keep their focus.

That's not just about red cards, either. After Fofana's sending off against Burnley, Rosenior said the draw added to a list of games after Wolves away, Crystal Palace away and Leeds at home where Chelsea "have conceded goals from moments of lack of concentration, lack of accountability".

Fofana will be suspended for the trip across London, while Marc Cucurella is out and Estevao is a doubt.

Romeo Lavia was back on the bench against Burnley and will hope to make his return from injury.