Ahead of their clash with Bournemouth, O'Neil highlighted the form of Cunha.
He said: “He's worked very hard and he's a really humble guy. When I first came, he was big enough and open enough to accept the gaps that he had in his game, and then he’s just gone head on into trying to tackle them and trying to piece the bits together.
"The most important bit in any footballer is quality, and that's the bit he has in abundance.
“All the other stuff you can work on with him, around positioning and mentality to defend and get back under the ball – all that is workable. What you can't help players with is the quality that they have and the understanding that they have, and Matheus is top level at that.
"We love having him here, he's an exceptional player, he’s incredibly important to the group and to the football club, and I look forward to working with him for as long as possible.”
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