Dimi Konstantopoulos set a new club record when he took his place between the posts, becoming the oldest player ever to play for the club.

He was in a side captained by Grant Leadbitter who was making his 500th career appearance and one that contained loan signing Rajiv van La Parra, who in making his Boro debut was playing his first game since October 6 and just his sixth of the season.

Steve Evans made three changes to the side beaten 2-0 at home by Scunthorpe on New Year’s Day. Rhys Bennett and Tyler Denton dropping to the bench, Durham-born Marcus Maddison missed out altogether.

In came Mark O’Hara, Ben White and Danny Lafferty, the latter two on loan from Brighton and Sheffield United respectively. Middlesbrough Academy graduate Callum Cooke was on the bench.

A bright start had United stretched and Paddy McNair drilled a low volley through a crowded box and inches wide.

Movement from Ashley Fletcher and Britt Assombalonga had the visitors stretched, then George Friend, who had earlier produced a timely tackle in the box at the other end, brought a save at his near post from Conor O’Malley.

Siriki Dembele was inches away with a low shot from outside the box, then Ivan Toney missed a glorious chance to open the scoring when firing over the bar to round off a move that had cut through the middle too easily for anyone’s liking.

Rudy Gestede flashed a powerful header towards goal but straight at O’Malley in the final chance of an open first half.

Van la Parra was replaced for the start of the second half by Lewis Wing, the plan always being to ease his way back into action.

Just over 90 seconds into the second half Wing fed a low ball into the Peterborough box, Marcus Tavernier set up Fletcher, his shot looped up and was pushed onto the bar by O’Malley and falling nicely for Britt Assombalonga to head in against one of his former sides.

Around two minutes later and the game was firmly under control as Fletcher strongly held off a determined challenge deep inside the Peterborough box and slid a low pass to George Friend who tucked home from closer range to register his first ever FA Cup goal.

If those goals were well-worked, the third was spectacular as Lewis Wing took aim from 25 yards and rocketed a shot into the top corner of O’Malley’s net.

Back to well worked for the fourth and again Wing was involved, receiving a shot pass from McNair he threaded through to Gestede who in turn set up Britt Assombalonga with a backheel that gave him time to drill home low from the edge of the box.

The scoring was rounded off on 86 minutes when Stephen Walker picked out McNair and a simple ball set up Ashley Fletcher whose neat finish with his back to goal added a fifth.

Scorers Assombalonga 47, 69, Friend 49, Wing 62, Fletcher 86

Boro: Konstantopoulos, Fry, Ayala, Friend, van la Parra (Wing 46), Leadbitter (Capt.), McNair, Tavernier (Chapman 75), Fletcher, Assombalonga, Gestede (Walker 74). Subs: Lonergan (gk), D Spence, Wood, Clayton.

United: O’Malley, Naismith, O’Hara (Godden 58), Tafazolli, White, Ward, Reed (Cooke 74), Woodyard (Capt.), Dembele (Cummings 79), Lafferty, Toney. Subs: Chapman (gk); Bennett, Cooper, Denton.

Referee: James Linington. Isle of Wight.

Yellow cards
Boro Leadbitter 45+1, foul
United White 33, foul

Attendance: 11,647 (1,226 Peterborough)