Arsenal's return to Premier League action was marred by a calamitous David Luiz display, after the defender was at fault for two Manchester City goals.
The Gunners were beaten 3-0 by Pep Guardiola's side at the Etihad Stadium, but Luiz's ill-fated appearance from the bench proved pivotal.
Luiz was brought on in the 24th minute after Pablo Mari was taken off injured, but the Brazilian was at fault for Raheem Sterling's opener.
He then hauled down Riyad Mahrez to give away a penalty and was sent off to cap off a miserable night, and effectively end the match as a contest.
The 33-year-old joined Arsenal last summer from Chelsea and according to Tony Cascarino, the Blues were surprised when the Gunners made their move to sign the defender.
The Brazilian centre-back had only just signed a new two-year deal at Stamford Bridge in May 2019, but left to join Arsenal three months later in an £8 million deal.
Luiz helped Chelsea to win the Europa League and finish third in the Premier League last season, but the Blues were happy to part company with the experienced centre-back, with Frank Lampard placing his faith in Fikayo Tomori, Kurt Zouma and Andreas Christensen.
And former Blues striker Cascarino revealed that his old side could not believe their luck when Arsenal came calling.
"David Luiz," he wrote in his column in The Times when asked to name the worst signing of last summer.
"When Arsenal bought the Brazil defender in the summer for £8m I know that Chelsea’s reaction was: ‘Wow, they've taken our poorest defender’.
"You have that familiar image of him chasing after a forward who has got behind him: opponents always know that the 32-year-old will give them space by wandering out of position.
"He is a fine footballer who sprays the ball around well but for a player with so much experience his defending is not good enough."
Chelsea's decision to sell Luiz looks like being further vindicated with the defender set to leave Arsenal after only one season in north London.
At the time, it was widely reported that Luiz signed a two-year deal when he joined the Gunners, but football.london understands the centre-back signed a 12-month contract with an option for a further season.
At present, that option has not been activated, leaving Arsenal head coach Mikel Arteta with the prospect of letting one of his most senior defenders leave at the end of the season unless an agreement can be found.
Speaking after the match on Wednesday, Luiz said he took responsibility for the result.
"It's my fault," he told Sky Sports. "The team did well, especially with 10 men. The coach is amazing, all the players are amazing, it was my fault.
"I should have taken a different decision in the last two months but I didn't.
"All about my contract, if I stay here or not. I have 14 days to be here and that's it. I should have tried to decide my future as early as possible, but I didn't.
"I don't want to use that as an alibi or excuse, it's my fault - that's it. I love to be here. That's why I continue to train hard."
