League One leaders Wigan Athletic have claimed an FA Cup giant-killing by clinching a 2-0 win over Premier League West Ham United in the fourth round of the competition.
Premier League outfit Huddersfield Town were taken to a replay in a 1-1 draw by Championship strugglers Birmingham City at the John Smith's Stadium, Steve Mounie opening the scoring in the first half before Lukas Jutkiewicz equalised on 54 minutes.
Coventry City ensured that at least one League Two side will be in the fifth round after winning at League One strugglers MK Dons as Maxime Biamou's second goal in as many games proved the difference.
In other results, Hull City beat Nottingham Forest 2-1, Middlesbrough were beaten 1-0 at home by Brighton & Hove Albion, Sheffield United defeated Preston North End 1-0, and Southampton overcame Watford by the same scoreline.
Results in full: Huddersfield Town 1-1 Birmingham City, Hull City 2-1 Nottingham Forest, Middlesbrough 0-1 Brighton & Hove Albion, Millwall 2-2 Rochdale, MK Dons 0-1 Coventry City, Notts County 1-1 Swansea City, Sheffield United 1-0 Preston North End, Southampton 1-0 Watford, Wigan Athletic 2-0 West Ham United