In-form Crysencio Summerville rescued West Ham in extra time as they avoided an FA Cup shock at League One Burton.

The substitute struck in the 95th minute to save the visitors with his sixth goal in seven games after they laboured at Pirelli Stadium.

Freddie Potts was sent off for a reckless challenge on Julian Larsson in the first half of extra time but the Hammers survived to reach the fifth round.

Manager Nuno Espirito Santo made 10 changes and the disjointed visitors struggled against a team 47 places below them and fourth-bottom in League One.

A plane pulling a banner protesting against West Ham owner David Sullivan and vice-chair Karren Brady flew over the stadium before the game and a limp performance would have done little to change the mood.

They may have won three of their past five Premier League games but the underlying frustration and anger with the running of the club remains, with the Hammers third-bottom of the table.

They struggled against an organised, disciplined but limited Burton who matched them for a forgettable 90 minutes.

Summerville, a late second-half substitute, finally offered a rare moment of quality early in extra time when he cut inside and his shot brushed Terence Vancooten to beat goalkeeper Brad Collins from the edge of the area.

Potts was then dismissed for a dangerous challenge on Larsson and Summerville missed a golden late chance as West Ham held on, despite Burton pressure.