Alfie Doughty’s in-swinging corner tempted Raya to come off his line to try and catch the ball inside his six-yard box.
However, Elijah Adebayo got there first, rising high above the Arsenal goalkeeper to head the ball into the Gunners net.
Lansbury, who played for both Arsenal and Luton, was commentating on the match on Soccer Special, via the Sky Sports website.
He criticised Raya for lacking presence in the lead-up to the goal and suggested this would see Aaron Ramsdale get a look-in once again.
“It’s another set piece. Raya came out for it and Adebayo was higher,” said Lansbury.
“Luton have done it again and Arsenal have it all to do. Luton have played well and if they keep the confidence up and they’ve got half a chance.
“Ramsdale back in, isn’t it? Raya has no presence about him there and it’s 2-2. It’s a fair challenge, he’s just misread the flight.”
The 28-year-old then made another mistake for Luton’s third, Ross Barkley’s shot squirming under him just a few minutes later.
Later on, Lansbury added: “Troubles in paradise for Arsenal with this No 1 spot…
“For Luton, every point is massive for them and they need every one they can get.”
