Tammy Abraham's last-gasp goal completed Chelsea's rescue mission following a shambolic first half in a breathless 3-3 draw at West Brom.

The Baggies were gifted three goals inside 27 minutes at The Hawthorns with Callum Robinson scoring twice after shoddy defending from Marcos Alonso and 36-year-old Premier League debutant Thiago Silva.

Kyle Bartley made it 3-0 after more poor work at a corner but Mason Mount's well-struck 55th-minute effort was backed up by substitute Callum Hudson-Odoi putting the finishing touch on a great Chelsea move.

West Brom then buckled under the sheer weight of pressure in five additional minutes as Abraham tapped in from close range after Sam Johnstone saved Mount's shot.

27 - Chelsea were 0-3 down after 27 minutes against West Brom - only against Manchester City in February 2019 (19 mins) have they been three goals down earlier in a Premier League match. Shock. pic.twitter.com/393NqERHu6
— OptaJoe (@OptaJoe) September 26, 2020

Robinson caught Chelsea cold inside four minutes with a fine drilled finish across Willy Caballero after Matheus Pereira had picked off Alonso's poor header.

Abraham missed a sitter and Timo Werner wastefully crashed against the crossbar before another error, this time Silva's dallying and slip, allowed Robinson to slide under Caballero to double the lead.

Incredibly it was 3-0 when Bartley unerringly slotted in from Darnell Furlong's downward header at Pereira's corner with Chelsea's defending again suspect.

Alonso and Mateo Kovacic were sacrificed for Cesar Azpilicueta and Hudson-Odoi at the break and a high-tempo Chelsea reduced the arrears with a crisp long-ranger from Mount that left Johnstone flat-footed.

A fine Chelsea move culminated in Hudson-Odoi linking brilliantly with Kai Havertz before coolly finding the bottom-right corner to really get West Brom nerves jangling with 20 minutes to go.

West Brom were penned further and further back as time wound down and Abraham earned Chelsea the point after reacting quickly when Johnstone could only parry Mount's effort, with a VAR check ruling Havertz had not handled shortly before.

What does it mean? Big-spending Blues must gel quickly

Chelsea may have just avoided defeat but after Lampard was backed by a spending spree in excess of £200million he will not have the luxury of the patience he was afford last season.

With new recruit Ben Chilwell to come in at left back and Edouard Mendy surely to take over in goal after arriving from Rennes – with Kepa Arrizabalaga again benched – you would expect Chelsea to shore up. They must do so quickly.

And here's to you Callum Robinson…

Robinson has three Premier League goals to his name, all against Chelsea (one was for Sheffield United). His first was, in truth, only a half chance despite Alonso's helping hand and he scored with both of his shots on target, while West Brom netted with all three of theirs as a team.

Lampard has no case for the defence

Silva was brought in on a free transfer to shore up a leaky backline as Chelsea spent big elsewhere. He was far from the only culpable party in a mind-boggling show of first-half ineptitude but he certainly did not help.

Chelsea have made three errors leading to goals this term, the same amount as the whole of last season. Throw in 42 away goals conceded since the start of last season, more than any other side, and there are still big defensive concerns for the Blues.

42 - Since the start of last season, Chelsea have conceded more away Premier League goals than any other side (42). Open. pic.twitter.com/Gvs4YhuWns
— OptaJoe (@OptaJoe) September 26, 2020

Key Opta Stats: Chelsea achieve rare feat

- Chelsea are the first Premier League team since West Ham in February 2011 to avoid defeat after trailing by 3+ goals at half-time, a game which was also 3-3 against West Brom at the Hawthorns.
- The Blues have conceded 3+ goals in successive Premier League away games against newly promoted sides for the first time since March 1997 (v Sunderland and Derby).
- Chelsea have failed to keep a clean sheet in 20 of their 21 Premier League away games under Lampard.
- West Brom are the first top-flight side to concede 11 goals in their opening three league games since Arsenal in 1963-64 (12).
- Havertz has been directly involved in 27 goals in just 28 appearances in all competitions in 2020 (18 goals, nine assists).
- Silva is the first outfield player to make an error leading to a goal on their Premier League debut since Issa Diop for West Ham versus Arsenal (August 2018).

What's next?

Chelsea switch focus to Tuesday's EFL Cup fourth-round tie at Tottenham, while West Brom are next in action at Southampton in the Premier League on October 4.