Colin Kazim-Richards's late goal stunned Arsenal as Blackburn Rovers reached the FA Cup quarter-finals.
Premier League sides Manchester City and Chelsea both scored unanswered 4-0 victories on Sunday.
Oldham striker Matt Smith repeated his FA Cup heroics with a dramatic injury-time equaliser to force a fifth-round replay against Everton.
Wigan, strugglers in the EPL standings, were 4-1 winners over Huddersfield with striker Arouna Kone bagging in brace.
Manchester United edged into the FA Cup quarter-finals with a 2-1 victory over Reading on Monday night.
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FA Cup Results
Saturday 16 February
Oldham Athletic 2-2 Everton
Arsenal 0-1 Blackburn Rovers
MK Dons 1-3 Barnsley
Luton 0-3 Millwall
Sunday 17 February
Chelsea 4-0 Brentford
Huddersfield 1-4 Wigan Athletic
Manchester City 4-0 Leeds United
Monday 18 February
Manchester United 2-1 Reading
FA Cup Fixtures
Wednesday 27 February
19:45 Everton vs Oldham Athletic
19:45 Middlesbrough vs Chelsea
Saturday 9 March
15:00 Manchester City vs Barnsley
15:00 Manchester United vs Middlesbrough OR Chelsea
15:00 Millwall vs Blackburn Rovers
15:00 Oldham Athletic OR Everton vs Wigan Athletic
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