During his half-season on Tyneside, Willock scored eight goals in 14 games – including a club record equalling second in seven, the same as Toon legend Alan Shearer.
Head coach Steve Bruce made Willock his number one transfer target this summer but had to be patient before the Gunners decided to cash in on their academy graduate.
Pundits and former professionals such as Darren Bent and Rio Ferdinand quickly slammed Arsenal for offloading Willock.
Bent, speaking to talkSPORT, said: “For Arsenal, it was the worst decision.
"I don’t know how Arsenal have let Joe Willock go. The guy scores goals from midfield man. I really like him.
"I don’t understand that. Newcastle have done unbelievable well to get him by the way, I think he’s a really good talent."
However, Howey has gone against the popular opinion, insisting Arsenal were right to sell Willock to his former club.
He told This Is Futbol: “I think Arsenal have got a good deal. Yes, he is a prospect but he wasn’t featuring in Arsenal’s team.
“To get £20million for someone who didn’t really get in their team, I think Arsenal have done well. It’s good business.”
Willock made his second Magpies debut at Aston Villa on Saturday afternoon, playing a full 90 minutes as Bruce’s side lost 2-0.
We’ve gathered the best of today’s Premier League speculation below…
Pundits and former professionals such as Darren Bent and Rio Ferdinand quickly slammed Arsenal for offloading Willock.