Mansfield stunned Premier League Burnley to reach the fifth round of the FA Cup for the first time in more than half a century.
The Stags, who sit in mid-table in League One, arrived at Turf Moor on a five-game winless run but they fought back from a goal down in impressive fashion to claim a 2-1 victory.
Burnley paid for not taking their chances in the first half, with Josh Laurent's 21st-minute goal all they had to show for their efforts at the break.
Rhys Oates headed in the equaliser in the 53rd minute and captain Louis Reed capped a fine individual performance with a spectacular winner from a free-kick 10 minutes from time.
It is the furthest Mansfield, who beat Sheffield United in the third round, have made it in the competition since 1975.
Burnley went into the game on a high after their first Premier League win since October over Crystal Palace in midweek, but boss Scott Parker made nine changes and this was a chastening
Crysencio Summerville (above) spared West Ham's blushes as he came off the bench to score an extra-time winner against League One Burton Albion and put Nuno Espirito Santos’ side into the last 16 with a 1-0 victory.
Summerville made it six goals in his last seven when he struck in the 95th minute of a poor contest, cutting in from the left and beating two defenders before hitting a shot which deflected off Terence Vancooten to beat Brad Collins.
The Hammers may have won three of their last five in the Premier League to offer renewed hope of avoiding the drop, but a side sporting 10 changes from the 1-1 draw with Manchester United laboured against a side 47 league places below them, fourth bottom of League One.
They finished the match hanging on after Freddie Potts was sent off in the 101st minute for a poor challenge through the back of Julian Larsson, with Jack Armer, Kain Adom and Kyran Lofthouse all flashing shots narrowly wide for the hosts.
Norwich booked their place in the fifth round as two late goals earned them a 3-1 win over West Brom at Carrow Road.
With the game delicately poised at 1-1, after Josh Maja cancelled out Paris Maghoma's opener, substitute Ben Chrisene produced a cracking finish to put the Canaries ahead with just eight minutes of normal time remaining.
January signing Mo Toure then put the icing on the cake in stoppage time by adding his fifth goal in three games to leave Albion boss Eric Ramsey still looking for his first win after seven matches in charge.
James Bree scored an extra-time winner to fire Southampton to a 2-1 victory at home to Championship rivals Leicester City.
Cyle Larin's penalty in first-half stoppage time put Saints on course for round five but Oliver Skipp's acrobatic equaliser early in the second half made it 1-1 at the end of normal time.
Bree then headed a 109th-minute winner after Republic of Ireland international Ryan Manning's free-kick had flicked off the head of Leicester substitute Patson Daka into his path at the far post.
Manchester City progressed with a far-from-convincing 2-0 win over League Two side Salford City.
Pep Guardiola's side thrashed their neighbours 8-0 last season but needed an early own goal from Alfie Dorrington and a late effort from Marc Guehi to prevail on this occasion at the Etihad Stadium.
