Brought back into the fold by former Owls chief Steve Bruce after being ostracised during the reign of Jos Luhukay, Westwood showed his credentials to the watching Monk in his first outing in charge at Huddersfield Town on Sunday.
Despite not being overly extended, the 34-year-old, named in a PFA divisional team line-up on three occasions in his career - including in the colours of Wednesday in 2014-15 – made a couple of key saves to thwart the Terriers en route to a clean sheet in the Owls’ 2-0 derby win at the John Smith’s Stadium.
Monk said: “Of course, Keiren has been one of the best keepers in the league.
“He has had some injury problems in recent seasons, but a fully-fit Keiren is one of the best keepers in this league - if not the best.
“It is vitally important that he made a couple of saves. He did not have a lot to do (on Sunday), but he made the saves and that is what he is there for.”
Another of Wednesday’s leading players in Barry Bannan also came to the fore in Sunday’s derby in West Yorkshire, with the Scot - wearing the captain’s armband in the absence of the injured Tom Lees – named as the man-of-the-match in the televised fixture following an assured performance.
It was a fitting way to mark Bannan’s 150th game for the Owls, with Monk under no illusions to his importance to the club.
“He still is (a big influence)”, the new Owls chief added.
“We have done well this summer to add a few fresher legs in certain areas; younger lads. Maybe there have been doubts put on those older heads over the last couple of seasons in terms of what the club needs to achieve.
“But the players have got quality and the older heads help those younger ones gel together.
“We know they have the quality and it is about getting that level of belief, work-rate and attitude to make sure that comes out on the pitch week in week out.”