The Wales defender was “technically dead” for over two minutes as medics fought to save his life.
Rushed to hospital and fitted with an implantable cardioverter defibrillator, Lockyer has been able to resume normal life but is yet to return to playing with Luton.
After the original game was abandoned with the score at 1-1, the 29-year-old was back at Bournemouth for the rearranged fixture 88 days on from the harrowing incident.
Lockyer’s presence initially galvanised Luton, who scored three times in the first half through Tahith Chong, Chiedozie Ogbene and Ross Barkley.
But Bournemouth hit back in stunning style after the interval thanks to strikes from Dominic Solanke, Illia Zabarnyi and two-goal Antoine Semenyo.
Third-bottom Luton sit three points adrift of fourth-bottom Nottingham Forest after blowing a golden opportunity to climb out of the relegation zone.
Forest will visit Luton in a crucial showdown on Saturday.
“We put ourselves in a good position. Of course it hurts,” Luton boss Rob Edwards said after Bournemouth became the third Premier League team to win when trailing by three at half-time.
“I don’t want to make excuses. We were the ones to blame. We should have seen the game out.”
Luton’s against the odds bid to extend their stay in the top flight pales in comparison to Lockyer’s own fight for survival.
Lockyer is unsure if he will ever play again after his second collapse, following an similar incident during Luton’s Championship play-off final victory against Coventry at Wembley in May.
For now, he spends his days getting used to becoming a father for the first time after his girlfriend recently gave birth to their baby daughter.
It was a heart-warming scene that greeted Lockyer when he stepped off the Luton team bus to loud cheers from waiting fans.
Lockyer was on the front of Bournemouth’s match-day programme, with mental health first aiders on hand to offer advice to fans at the stadium about cardiac health.
‘They are heroes’
“I’m quite numb to the whole thing but being back here, I came into the tunnel area and saw the paramedics that saved my life. I recognised them straight away,” Lockyer said in a pre-match interview.
“What do you say other than thank you? They are heroes and they saved my life. I got a little bit emotional.”
A banner in Luton’s orange and white colours displaying an image of Lockyer’s smiling face was held up in the away end.
He walked onto the pitch just before kick-off and shook hands with the life-saving medics.
Given a standing ovation from all four sides of the stadium, Lockyer was visibly moved as Bournemouth and Luton fans chanted his name.
In the ninth minute, Jordan Clark’s pin-point cross picked out Chong and he planted a header past Neto as Lockyer celebrated in the stands.
Luton doubled their lead in the 31st minute when Alfie Doughty’s clever cut-back invited Ogbene to slot home from close range.
Barkley bagged Luton’s third goal in first-half stoppage time, blasting past Neto after breaking Bournemouth’s offside trap.
But Solanke started Bournemouth’s escape in the 50th minute with a powerful strike from inside the area.
Both sets of fans shared a round of applause in the 59th minute to mark the time of Lockyer’s collapse.
Just three minutes later, Zabarnyi had Luton’s nerves jangling when he headed home from a corner.
Luton’s meltdown was complete in the 64th minute as Semenyo drilled past Luton keeper Thomas Kaminski.
And there was even worse to come for Luton in the 83rd minute when Semenyo produced another blistering strike to leave Lockyer and company stunned.
© Agence France-Presse
Photo: Twitter @addojunr