The England international has done little wrong since joining for £50million in 2019, although a serious injury last November ruined his season.
Now he faces a huge challenge competing against Cucurella, a Spain international who is one year younger and at £62m is the fourth most expensive signing in Chelsea history.
The Blues are arguably overstocked on the left-side of their defence, and Chilwell is still battling back to full fitness after that knee injury. After starting the first game of the campaign at Everton, Chilwell has made just one appearance off the bench.
Privately, the 25-year-old hoped this season would be a return to normality so he can firmly establish himself as England’s first-choice left wing-back option.
That mission seems under threat by Cucurella, but Saturday’s match against Leicester offers the duo hope of fitting in together.
Kalidou Koulibaly’s red card in last weekend’s 3-0 defeat at Leeds means Chelsea need to draft in another left-sided central defender.
Rather than call up Trevoh Chalobah or Ethan Ampadu, Thomas Tuchel is expected to move Cucurella across to centre-back. Chilwell will then step into the left wing-back spot, giving Tuchel a first chance to start the two together.
It is a match where 5ft 7in Cucurella will be tested by aerial duels at the heart of the defence, and Chilwell will be given the chance to show his ability again as he comes back from injury.
If both succeed, it will offer a vision of how the pair can co-exist.