It has been all Ajax but here come Chelsea now down their left. Callum Hudson-Odoi and Marcos Alonso engineer a one-two - but Alonso's return is a tad too heavy. He would have been in!

Steady now! Chelsea keeper Kepa pings a pass straight to an attacker in red and white but Fikayo Tomori does brilliantly to step across and make the challenge. Chelsea just look a touch rattled.

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

It was great anticipation by Joel Veltman. He saw the loose pass by Mason Mount and stepped in. He drove forward and no Chelsea player came out to meet him so he struck it just wide of the post.

The neutrals will be pleased to know that Ajax 2019-20 are just as much fun to watch as Ajax 2018-19. So much tempo. They win a corner, Donny van de Beek slams a volley in but it's right into the abdomen of Kurt Zouma.

I expected Van de Beek to move on this summer to be honest. Cracking player.

Intense pressing from Ajax, they strip the ball from Chelsea twice in quick succession near their own goal. A bit nervy at the back.

They turn the ball over again and Ajax defender Joel Veltman steps forwards and piles a drive wide from 25 yards or so.

Fikayo Tomori's movement from the corner is excellent, he loses his marker but mistimes his jump and rather slices the header across goal. Breathless start.

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

Fikayo Tomori can breathe a sigh of relief. It's a seriously bad mistake he made just inside the centre-circle. He brought it down on his thigh but had another touch and got dispossessed.

Really enjoyable and open start. Chelsea counter down their right and captain Azpilicueta wins another corner.

That's how Ajax can come at you! Chelsea defender Fikayo Tomori takes a heavy touch in the centre circle and the men in red and white sweep forwards in numbers. It goes out wide, is cut back for Donny van de Beek, and his shot is blocked by the hands of Marcos Alonso.

Penalty?! It was a good shout - but Chelsea are reprieved by an offside flag in the build-up...

Image source, Getty Images

Chelsea win a corner in the first minute...

Ajax keeper Andre Onana comes and punches it away.

And away we go!

These early kick-offs are often a bit flat - it's absolutely roaring in Amsterdam. Chelsea in a very sharp black kit tonight.

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

Tonight is a huge occasion for Chelsea. If they come away with nothing it's a huge uphill battle with Ajax at home and Valencia away to come next. But a win here for Frank Lampard will surely be the best result of his managerial career so far.

A Belgian test for the holders and a humdinger at San Siro.

Any shocks on the cards?

Image source, Getty Images

Lille v Valencia (20:00 BST)

Benfica v Lyon (20:00 BST)

Inter v Borussia Dortmund (20:00 BST)

Slavia Prague v Barcelona (20:00 BST)

RB Salzburg v Napoli (20:00 BST)

Genk v Liverpool (20:00 BST)

Here come the sides in Amsterdam. Looks a superb atmosphere.

Image source, Getty Images

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

Chelsea have invested a lot of money, time and energy into developing players and so far, up until this season, these players didn't have a clear pathway into the team to develop and become great.

To be mentioned in the same breath as Ajax, as a club to have young players coming through, is such a huge compliment for Chelsea because you've only got to walk into this stadium and it's filled with young ex-players on the walls, like Zlatan Ibrahimovic.

If you're just joining us...

Ajax: Onana, Dest, Veltman, Blind, Tagliafico, Alvarez, Martinez, Ziyech, van de Beek, Promes, Tadic. Subs: Bruno Varela, Schuurs, Neres, Huntelaar, Mazraoui, De Jong, Marin.

Chelsea: Arrizabalaga, Azpilicueta, Tomori, Zouma, Alonso, Jorginho, Kovacic, Hudson-Odoi, Mount, Willian, Abraham. Subs: Caballero, Giroud, Pulisic, Batshuayi, James, Emerson Palmieri, Gilmour.

Referee: Ovidiu Alin Hategan (Romania)

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

Chelsea are rewarding Callum Hudson-Odoi for wanting to stay with a new contract and minutes on the pitch. His performances have warranted that. For a young player to come back (from injury) and be able to physically cope with the demands of top-flight football in the way that he has has, game after game, is quite rare. Normally they'd be filtered in.

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Aged 18 years and 350 days, Callum Hudson-Odoi is the youngest player to start a Champions League match for Chelsea since Josh McEachran in December 2010 against Marseille (17y 282d).

At 26 McEachran may be the youngest veteran in the game. He's been around an age!