Full-time: West Ham 2-1 Liverpool
- Angelo Ogbonna headed home Dimitri Payet's free kick in the final seconds of extra-time to secure a fifth-round trip to Blackburn Rovers
- Michail Antonio gave West Ham the lead with a fine volley on the stoke of half-time
- Philippe Coutinho returned from a hamstring problem to equalise with a clever free-kick
- Injury-plagued striker Daniel Sturridge came on as a second-half substitute to make his first appearance since 6 December
- Hammers lost centre-back Winston Reid to a hamstring injury
That is all for this particular live blog. Thanks for joining us and stay tuned to IBTimes UK for the latest reaction.
Captivating late drama in east London as Ogbonna pops up in the 121st minute with his very first goal in English football that sends West Ham through to the last 16 and avoids a tense penalty shootout.
Bilic's side will now face Blackburn Rovers at Ewood Park on Sunday 21 February.
West Ham 2-1 Liverpool
West Ham win a free-kick on the right-hand side following Lucas' foul on Valencia. Payet then steps up to send in a deep ball that Ogbonna, soaring high above Flanagan and Stewart, heads powerfully past Mignolet and into the far corner.
Surely that's the goal that will send the Hammers into round five.
Goal: West Ham 2-1 Liverpool (Angelo Ogbonna)
Two minutes of added time signalled by the fourth official.
Excellent close control on display by Sturridge as he weaves through Collins and Noble before having the ball knocked away by Ogbonna.
He then wins a corner off Collins with an attempted flicked finish at the near post and Flanagan goes close with a header.
West Ham have long since made their last change so Valencia comes back on for the final few minutes. It will be interesting to see if he takes a penalty, should there be no winning goal.
The stretcher comes on for Valencia but he eventually leaves the field under his own volition.
The West Ham supporters cry for a free-kick after a tough challenge from Flanagan on Carroll, but referee East plays advantage. The Liverpool right-back is a tad fortunate not to be cautioned for that.
Another injury delay now as Valencia receives treatment after being caught on the follow through from Lucas' committed block.
Origi is the next Liverpool player to try his luck, but it's a difficult angle and his shot was never likely to test Randolph.
Flanagan then dispossesses Payet but Benteke's wild effort is dragged well wide.
Milner finds fellow sub Sturridge and the striker sprints forward with pace. With Collins backing off, he produces a fierce left-footed drive that whistles just over.
After a short break, proceedings are back underway. Is there a winner to be found late on here, or are we destined for the lottery of spot-kicks?
15 minutes away from a penalty shootout...
Half-time in extra-time
West Ham 1-1 Liverpool
Another opportunity for Benteke as he heads Origi's cross narrowly over the top.
Lucas then concedes a corner during a challenge with Payet but Smith does well to head clear at the front post.
Liverpool are going to make their final substitution now as James Milner comes on for Pedro Chirivella.
Smith must be fine to finish the game.
An unmarked Noble lets fly with an accurate shot from distance after receiving possession from Payet. Mignolet gets across to make the save.
At the other end, Benteke has two chances to score. First he sees a volley drift wide of the post, then he is sent clean through only to be thwarted by the legs of Randolph.
That will not do his fragile confidence much good at all.
Horrible miscue from Aaron Cresswell after Moses wins a corner from Smith, who is currently clutching his hamstring in pain.
It could just be cramp, although Klopp does have one change remaining if he cannot carry on.
East blows his whistle and the first period of extra-time is upon us.
That was unquestionably a more entertaining affair than the original tie at Anfield last month. There have been no shortage of chances, penalty appeals and talking points.
Klopp will be pleased with his young side and he has enough senior players on the field now to make the difference. West Ham, who have used all three of their substitutes, will be relying upon the likes of Antonio, Moses and Payet to create for Valencia.
End of 90 minutes
West Ham 1-1 Liverpool
One last half-chance for the hosts as Obiang breaks forward before shooting wide.
We are heading to extra-time at the Boleyn Ground.
West Ham appeal for handball as a delivery from the right strikes Lucas. The referee does blow his whistle, but it's for a push from Carroll on Stewart.