It did not take long for Chelsea to run out of patience with Frank Lampard following significant investment in their first-team squad during the close season.

Chelsea spent in excess of £200million on reinforcements for the 2020-21 campaign but with the club ninth in the Premier League and 11 points off top at the midway point, they dispensed with the services of their head coach on Monday.

Lampard arrived just 18 months ago with the club under a transfer embargo and was lauded for his faith in youth during a debut campaign that yielded a top-four finish and an FA Cup final appearance.

However, Chelsea have not managed to maintain an upward trajectory this season and after a run of two wins in eight Premier League games the decision was taken to cut ties with the club legend.

It is fair to say some of Chelsea's new arrivals have not lived up to expectations this term and we look at the numbers behind their performances.

Timo Werner – £45m from RB Leipzig

Werner arrived from Leipzig with big expectations having been involved in 36 league goals (26 scored, eight assisted) in 2019-20 – a tally only bettered by Robert Lewandowski (38), Ciro Immobile (45) and Lionel Messi (46).

He did not take long to find his stride, having a hand in 11 goals (eight scored, three assisted) in a 10-game stretch in all competitions between September and November.

However, the only goal he has scored in 15 appearances since the end of that streak came against Morecambe in the FA Cup third round – it ended an 827-minute drought in all competitions.

He is without a goal in 11 Premier League outings and his difficulties in front were compounded by his failure to convert from the penalty spot against Luton Town on Sunday.

Kai Havertz – £71m from Bayer Leverkusen

Alongside Werner (14) and Tammy Abraham (15), Havertz (10) is one of just three Chelsea players to have been involved in at least 10 goals in all competitions this season.

However, half of those have come against lower-league opposition – he scored the first hat-trick of his senior career against Barnsley in the EFL Cup in September, and versus Morecambe in the FA Cup this month had a goal and an assist.

When looking at his figures from the Premier League, he has just one goal and one assist in 16 appearances – 11 of which have come from the start.

Lampard seemed to struggle to figure out how to get the best out of versatile forward Havertz and given his price tag that will be high on the agenda for his replacement.

Ben Chilwell - £45m from Leicester City

A plantar fascia injury delayed Chilwell's Chelsea debut but he was quick to make an impact, becoming just the third Blues player to both score and assist on their Premier League debut, joining Deco and Alvaro Morata.

Within 13 games he had already matched his career best of four Premier League assists in a single season, while his six goal involvements in that time frame was the same as he managed across the entirety of 2019-20 for Leicester.

Crosses from the full-backs were a key part of Lampard's approach and Chilwell's 82 in open play is second to Reece James' 97.

But while 24.7 per cent of James' deliveries were accurate, only 13.4 of Chilwell's were - the third-worst rate of any Blues player to find a team-mate with at least one cross in open play.

Hakim Ziyech – £33.3m from Ajax

An assist for Werner in a pre-season friendly against Brighton provided promising signs, but a knee injury meant his competitive debut did not arrive until October.

He has registered two goals and four assists in 17 appearances in all competitions, but only Mason Mount (2.5) has created more chances per 90 minutes than Ziyech (2.4) this season (all comps).

Furthermore, he creates 0.8 Opta-defined 'big chances' per 90 minutes, which is the most of any Chelsea player to have featured in more than two games.

His expected assists in open play per 90 minutes of 0.21 ranks joint-seventh alongside Kevin De Bruyne (among players to have played at least 450 minutes), so with some better finishing his impact may look more impressive on paper.

Edouard Mendy – £22m from Rennes

After Kepa Arrizabalaga committed three errors leading to goals in as many Premier League appearances to start the season, bringing in Mendy from Rennes appeared an astute decision.

He kept nine clean sheets in his first 12 appearances in all competitions, but in his subsequent nine outings he has shut out the opposition just twice and conceded 13 goals.

In the Premier League, Mendy has let in 12 goals from an expected goals on target (xGOT) of 10.8, meaning he has let in one more goal than would have been anticipated from the chances he has faced.

That is the joint-eighth worst in the league among keepers to have played over 900 minutes.

Thiago Silva – free transfer

Although he became the first outfield player to make an error leading to a goal on their Premier League debut in two years when his loose control was seized upon by Callum Robinson in a 3-3 draw with West Brom in September, Silva's experience seemed to significantly improve Chelsea's defence.

Only Kurt Zouma (64.6 per cent) has a better duel success rate than Silva's 63.5 among players to have played at least 10 games in all competitions, and he has helped them tighten up when defending set-pieces.

Excluding goals scored directly from free-kicks, Chelsea conceded 13 times from set-pieces in the Premier League in 2019-20, while this term they have only shipped five from dead balls and one of those came when Silva was not in the side.

The Brazilian has also made them more of a threat from set-plays, providing two of the nine goals Chelsea have scored in such situations.