Alexis Mac Allister was the coolest man in the Amex, converting a 90th-minute penalty as Albion came from behind three times to share six goals with Brentford.
Kaoru Mitoma had earlier become the first Japanese player to score seven Premier League goals and Danny Welbeck was also on target after Brentford twice led in the first half through Matthias Jensen and Ivan Toney.
Ethan Pinnock made it 3-2 early in the second half but thereafter it was the David Raya show as the Brentford keeper made a string of superb saves. It looked like ending in frustration for Albion, but when Aaron Hickey was penalised for a handball spotted by the VAR, Mac Allister stepped up to make it 3-3 and lift Albion up to sixth in the table.
The atmosphere was terrific once again and the hosts began brightly, but Albion fans were stunned when Brentford took a 10th-minute lead. Matthias Jensen’s whipped cross from the left was headed firmly past Jason Steele by Jansson, who’d got a yard in front of Lewis Dunk and took the chance with aplomb.
When Steele handled a back pass moments later Albion had everyone on the line to defend the free kick 11 yards out which Jensen smashed goalwards but the wall did it’s job and Albion cleared.
It had been a frenetic start but Albion kept coming. Solly March cut inside past two challenges but two slight deflections took the sting off his shot and Raya was able to save but the Spanish keeper was helpless moments later when the hosts drew level. His opposite number Steele picked out Mitoma with a superb pass and Mitoma scorched past Hickey and nonchalantly lifted the ball over Raya and into an empty net.
But the celebrations were cut short. Albion didn’t clear their lines and Toney restored Brentford’s advantage with a right-foot shot past Steele from close range.
There was little time for the crowd to catch their breath before Albion hit back to make it 2-2 in the 27th minute. March teased a lovely cross from the left and Welbeck generated terrific power at the far post to head firmly past a helpless Reya.
Incredibly, both sides could have gone in front within the space of 60 seconds. Jansson’s spectacular bicycle kick dropped a yard wide then Mitoma was a toenail’s distance from converting March’s cross at the other end. Mitoma then left Hickey in his wake after Albion moved the ball patiently from left to right but Welbeck couldn’t get enough power on his effort to stab Mitoma’s cross past Raya, who then got right behind Dunk’s long-range free kick.
The Brentford keeper was being kept busy. Mac Allister forced Raya to push away a curling effort that was heading for the far corner before Levi Colwill rose unmarked but headed Gross’s set-piece delivery over the bar. Raya made another save in stoppage time to prevent March’s low effort from sneaking into the far corner.
Albion would have felt they had deserved to be in front at the break. Instead they conceded again four minutes into the second half when Pinnock met Bryan Mbeumo’s deep free kick from the left at the far post and stabbed the ball home.
Albion had to come from behind again and they set about the task with verve. Moises Caicedo forced Raya to turn his powerful drive over the bar. The resultant corner sat up nicely for Pervis Estupinan but he blasted his effort into the North Stand.
Raya was certainly embellishing his credentials. He produced a fingertip save to deny March, who had been played in by Mac Allister’s exquisite pass, then got down to save Joel Veltman’s powerful shot after Mac Allister’s driving run at the heart of Brentford’s defence.
With 15 minutes to go March dragged his shot wide as Brentford retreated into a low block to hold onto their advantage.
It looked like ending in a frustrating afternoon for Albion but with three minutes to go referee Oliver awarded a penalty for handball by Hickey as he tried to stop substitute Deniz Undav from lifting the ball over Raya. After a check at the pitchside monitor referee Michael Oliver pointed to the spot and Mac Allister made no mistake, sending Raya the wrong way.
There was still drama to come. Hickey was perhaps fortunate to get away with another handball from March’s cross and Albion had to defend two dangerous set-pieces at the other end. Honours even and the standing ovation afforded to both teams at the end was richly deserved.
Albion: Steele, Veltman (Enciso 72), Dunk, Colwill, Estupinan (Buonanotte 83), Gross, Caicedo, March, Mac Allister, Mitoma, Welbeck (Undav 83).
Subs not used: Sanchez, Webster, Ayari, Gilmour, van Hecke, Moran.
Referee: Michael Oliver