Chelsea host Barcelona in a UEFA Champions League round-of-16 clash that has the makings of a classic at Stamford Bridge on Tuesday with many labelling the tie a season-defining one for both sides.

Despite their contrasting fortunes in domestic competitions, the European powerhouses will know that nothing comes close to the Champions League and it’s not a stretch to say that plenty of jobs are on the line.

Don’t miss: Chelsea midfielder Cesc Fabregas relishing Barcelona clash

Ahead of the mouthwatering clash in West London, The Statesman takes a a look at the five key players that are likely to play a pivotal role on Tuesday night:

Thibaut Courtois (Chelsea)

Considering Barcelona’s imperious form this season, it won’t be a punt to predict that Thibaut Courtois will be the busier of the two goalkeepers on Tuesday night.

For Chelsea may be playing at home, but Ernesto Valverde’s side will be dominating possession and will pepper Courtois’ goal with shots from kick-off.

While Conte’s men were almost impervious last year, this time around they have found it difficult to keep clean-sheets and Courtois has been left high and dry by his defence on more than one occasion this season.

With all the speculation surrounding a purported move to Real Madrid in the summer, a standout performance against their arch-rivals would do his prospects no harm but would in fact, make his case stronger as the Blues offer him an improved deal.

Courtois faced off plenty of times against Barcelona during his Atletico Madrid days so is no stranger to the La Blaugrana’s attacking prowess, but after Petr Cech’s stupendous displays against Barcelona in the UEFA Champions League, the Belgian has some big shoes to fill.

So far, Courtois had proven to be an able replacement but European nights such as these make you a household name and the 25-year-old will look to enhance his burgeoning reputation and prove he’s worth the hype with a superlative performance against the Catalan giants.

Lionel Messi (Barcelona)

It may seem incredulous, but Messi is yet to score against Chelsea in their last eight meetings.

Antonio Conte had stressed that the past doesn’t count for much but one can bet the diminutive Argentine will be champing at the bit to set the record straight once and for all.

With Philippe Coutinho ineligible and Ousmane Dembele not settled yet, Messi is likely to lead the line alongside Luis Suarez and so far the duo has been in terrific nick.

Messi’s tally of three goals and an assist in Europe suggests a dip in form, going by his stratospheric standards, but the 30-year-old is so much more what the stats table show.

The ability to take out three players with one mind-bending dribble before registering a ‘pre-assist’ is what the statistics don’t tell you and there can be no denying that Messi is the creative fulcrum of Ernesto Valverde’s side.

Juventus managed to shut him down last season enroute to a famous win and Conte will have to take a leaf out of his former side’s book as he prepares for Messi’s visit.

However, even if one manages to keep Barcelona’s No.10 quiet, Barcelona have a plethora of attacking talents and Messi’s strike-partner, one who will feel the ire of the home support, can win games on his own.

Alvaro Morata (Chelsea)

Morata, after lifting ‘Big Ears’ twice during his two stints with Real Madrid, knows what it takes to win in the continental competition, but the pressure is mounting on the lanky Spaniard, who’s on the verge of being labelled an expensive flop.

After a bright start, niggling injuries and a lack of form have curtailed his progress in West London but the Spaniard could endear himself to the Blues faithful should he regain his scoring touch against a side he no

With their Premier League title defence in tatters, Europe is the way to go for Morata and Co.

Easier said than done for in front of them are a team that conceded just once in the group-stages.

While all the acclaim falls at their forwards, Barcelona’s defence had done a remarkably top-class job in keeping things tidy at the back but can Morata hurt them?

Excellent in the air, able to score with both feet, the 25-year-old Spaniard possess all the tools required for a top class centre-forward, but why hasn’t he found the back of the net in the past eight games?

At £60 million, he certainly didn’t come on the cheap and questions will continue to be asked the longer his barren run continues but should he return to form against the Catalans, all will be forgiven.

The travelling supporters are likely to boo his every touch due to his Madrid past, which will spur him on, but will he be able to best the likes of Gerard Pique at Stamford Bridge?

Luis Suarez (Barcelona)

One man bound to get a hostile reception on Tuesday is Luis Suarez.

For the Uruguayan, perhaps the finest No.9 in world football, etched his name into the infamous list after biting Blues defender Branislav Ivanovic on the shoulder during an fiery Premier League clash at Anfield during his Liverpool days.

Chelsea fans will certainly not have forgotten but they will be wishing the 31-year-old has an off day and Suarez’s poor record in Europe this season (no goals and just one assist) will give them hope.

However, the South American hitman has been on fire in the La Liga of late and he will give the Chelsea back-line a tough time with his directness.

Clearly not ruffled by physical defenders, Suarez blends craft with graft and the tireless Uruguayan will fight tooth and nail to give Blaugrana an away goal or two.

Suarez lives for goals and while he does plenty of other things, notably harrying opposition defenders whenever they have possession, he’ll have to be at his prolific best if La Blaugrana are to go back to the Nou Camp with a definitive advantage.

Eden Hazard (Chelsea)

Another Chelsea player linked with Real Madrid, Eden Hazard will be the cynosure of all eyes when the Barcelona come visiting on Tuesday.

The 27-year-old Belgian is probably the player whose game gets as close to Lionel Messi’s as possible.

Their low centre of gravity enables the two drift past players with ease before utilising their low backlift to find the back of the net or setting up a teammate with a delightful assist.

And while the similarities are plenty, Messi’s sheer consistency sets him apart from the rest and that is something Hazard will look to ‘copy’.

Is this the most important game in Chelsea’s season?

After their travails in the Premier League, it would be hard to disagree and the Blues will look to their talismanic winger to stand tall (pun unintended) when the mighty Catalns come visiting.

Despite their dominant form this season, La Blaugrana are not invincible, far from it in fact.

Hazard will be a marked man from kick-off but the fact that he’s used to the extra attention will hold in good stead as he puts the world on alert that he’s not just a pretender to Lionel Messi and Cristiano Ronaldo’s crown.

How he links up with club-record signing Morata will likely determine Chelsea’s fortunes in the tie and if the two get going, a home win might just be on the cards.