West Ham boss David Moyes is wary of tonight's opponents Aston Villa.
Moyes believes clever work in the transfer market is behind Villa's improvement this season.
He said, "Dean Smith said last year they brought in one or two players who didn't quite work or took time to settle but, after scraping through last year, this year they have signed very good players and greatly improved players in their team like Jack Grealish, John McGinn, Tyrone Mings and Ezri Konsa.
"Grealish is a really improved player. From my point of view, he's probably the bets player in Premier League at this moment in time. He's shown what he can do and really done such a big job for Aston Villa so, for me, he's playing as well as any player in the Premier League.
"Then they've added to it with people like Ollie Watkins and one or two others as well.
"They've got a good side and recruited very well and that's the reason why they're in the position they're in."
