How many games can you remember where Chelsea have been in complete control to see out a win in comfortable fashion this season? Not many, right?

Few teams can dominate their opponents for a full 90 minutes regularly and stop them getting shots at goal. If it were that easy, you would see lots of sides battling to be champions of their respective division.

But one of the main failings head coach Liam Rosenior is struggling to change in the Chelsea squad he inherited in January is their consistent inability to see a game out even when they are on top.

Chelsea were poor for long periods in their 4-2 FA Cup fifth round win away at Wrexham. But when they went 3-2 up against the Championship side, who had been reduced to 10 men due to George Dobson being sent off, with 24 minutes of extra time remaining it should have been comfortable from there.

And yet you could not tell Chelsea had a man advantage as well as the superior know-how from playing in a league above. They kept pushing forward in manic fashion, leaving huge gaps in behind for Wrexham to exploit. But for a tight offside call late on against Lewis Brunt, who saw his close-range header correctly ruled out by VAR, the game would have probably finished 3-3 and been decided by penalties. It should never have got that close.

This was a heavily rotated Chelsea side and not the first choice XI but there are many other examples — and that is not even including under any of Rosenior’s predecessors — when Chelsea have had their regulars on the pitch and were unable to take the heat out of a contest they were leading in.

Just go back to the 4-1 win over Aston Villa three days earlier. At 3-1, Jorrel Hato passed it straight to Emi Buendia outside of Chelsea’s penalty area. It led to Ollie Watkins being played through with goalkeeper Filip Jorgensen to beat. The striker hesitated and allowed Trevoh Chalobah to tackle. Had Watkins scored as he should have done, the mood at Villa Park as well as among the home team’s players would have shifted from despair to fresh hope.

Jesse Derry, left, joins Joao Pedro to celebrate the Brazil forward’s goal in extra time (Peter Powell/AFP via Getty Images)

They also led bottom club Wolverhampton Wanderers 3-0 at half-time in February, switched off and allowed Tolu Arokodare to score from a set piece nine minutes into the second half to make the rest of the fixture far more awkward.

In the following league match they were 2-0 up at home against Leeds United when Moises Caicedo dived in needlessly to give away a penalty. They ended up drawing 2-2. It was a similar story versus Burnley 11 days later with Zian Flemming heading in an equaliser in injury time.

It is a facet of Chelsea’s play Rosenior concedes must get better. He first became aware of it in his second league game in charge away at Crystal Palace when they were 3-0 up and played with an extra man for the last 18 minutes after Adam Wharton was sent off. They could have let in more than just Chris Richards’ goal in the 88th minute.

When asked about Chelsea’s struggle to see games like the Wrexham one out, he replied: “It was the same against Crystal Palace about six weeks ago when I first joined. We have control and we need to find a way to get the game managed better. We need to find a way. We are playing as a team but we’re playing against very good opposition at times, who are going for it.

“I am still learning about this group. I have been at the club for two months. I am still learning about what our players are capable of, how they see the game. But we have put ourselves in a really strong position in every competition since I have joined. It is 15 games in, with 10 wins, two draws and three defeats. It is not a bad place to be. What we now have to do is make sure that we capitalise on the position we are in at all the competitions.”

Lewis Brunt’s finish would have drawn the tie level but it was ruled out for offside (Carl Recine/Getty Images)

And therein lies the hub of the issue. Rosenior’s record since succeeding Enzo Maresca is pretty good but it could be so much better. Those two draws he mentioned were bad ones against Leeds and Burnley. The four dropped points could be the difference between Chelsea qualifying for the Champions League via a top five finish at the end of the season or not. Add them to their tally and they would be sitting third in the table rather than fifth (only above Liverpool on goal difference).

The three defeats all came against Arsenal and that is telling. Against lesser opposition, you may be able to get away with not being able to keep calm as well as your shape. But the best sides will punish you. Arsenal proved that by knocking them out of the Carabao Cup at the semi-final stage and by beating them 2-1 in the Premier League last week.

As they compete on three fronts in the run-in, the task and pressure to win matches will be even harder. They face Champions League holders Paris Saint-Germain in the round of 16, with the first leg away on Wednesday night. Their bid to win the FA Cup has seen them play lower league opposition in every round thus far. Arsenal, Manchester City and Liverpool are among their possible opponents in the last eight.

Chelsea can still make this season a success. But it won’t be if they keep making the same mistakes.