Mark Bonner described his Cambridge United’s side’s FA Cup third round giant-killing at Newcastle United’s St James’ Park as a fairytale after watching Joe Ironside’s second-half goal stun the struggling home side. It represented a tactical triumph for Bonner, a 36-year-old new-school manager who never kicked a ball professionally and worked his way up after beginning his career coaching Cambridge’s under-eights. After promotion from League Two last season, Cambridge are mid‑table in League One, 41 places beneath Newcastle on the ladder. “What an occasion,” he said. “There’s always a fairytale and an upset in the FA Cup and we hoped it would be us this year but then we saw how strong Newcastle’s team-sheet was. “Our goalkeeper [Dimitar Mitov] was brilliant but I am so proud we kept them at bay. We only got promoted last year so keeping a clean sheet is an incredible achievement.” It left the Middlesbrough-born Ironside, who grew up idolising Newcastle’s former centre-forward Alan Shearer, celebrating in front of the 5,000 Cambridge fans. Bonner added: “This day will be remembered for decades. These are the moments you never forget and you never know how long it will be before you experience anything like it again. “Newcastle’s an incredible football club and an incredible city and the noise got big at times but we coped with the atmosphere and, although we rode our luck at times, we also had periods of control and managed to turn it into a great day for our supporters.” While Cambridge operate on one of the third tier’s tighter budgets, Newcastle, with their Saudi Arabian owners, are theoretically the world’s wealthiest club but are facing relegation from the Premier League after winning one game all season. They played poorly here in front of their chairman, Yasir al-Rumayyan, who had flown in from Riyadh specially for the game but departed, grim-faced, flanked by a quartet of bodyguards. Eddie Howe, who revealed that Rumayyan visited the dressing room to offer Newcastle’s players something of a pep talk after the final whistle, said: “We are desperately disappointed. “We wanted to win but we played a very strong Cambridge team and we couldn’t break them down. I have to give credit to Cambridge’s players and their manager.” “We had some good moments but their goalkeeper was outstanding and we lacked the killer instinct every team needs.” Newcastle entertain Watford in a relegation six-pointer on Saturday and Howe said: “We have some season‑defining league games coming up and I just hope this defeat doesn’t damage our players’ confidence. “We just have to take it on the chin and bounce back.”