Manchester United's Under-21s were beaten by Hector Bellerin's late winner despite a resolute defensive display.
Charni Ekangamene's first goal at this level, with the Reds' only noteworthy shot on target, opened the scoring but the home side responded quickly thanks to a Conor Henderson penalty.
A dreadful surface at Underhill did not help either side develop a passing game and the first half was littered with free-kicks. Bellerin was booked for a foul on Jesse Lingard early on and that set the tone for some strong challenges from both sides.
Pierluigi Gollini was equal to a Henderson free-kick but the Reds defended stoutly until Isaac Hayden was allowed a far-post header from a free-kick after he had been involved in a flare-up with Sean McGinty. Thankfully, the Gunners forward nodded wide.
A moment of magic by Ekangamene illuminated proceedings on 40 minutes as the Belgian midfielder rocketed a rasping drive past Emiliano Martinez after Larnell Cole latched onto a Marnick Vermijl pass down the line to pull the ball back to the edge of the area.
The lead was short-lived, however, as the impressive Bellerin was felled by Lingard inside the box and a rather soft penalty was awarded. Up stepped Henderson to hammer his spot-kick straight down the middle after Alexander Büttner, rather than Lingard, was shown a yellow card - presumably for dissent.
Despite the goals, things remained untidy after the interval and Lingard did receive a caution after a reckless tackle on Francis Coquelin, even if the Frenchman made a meal of it. Adnan Januzaj, working his socks off as a lone attacker with little reward, drifted a rare shot well wide before drawing a booking out of Ignasi Miquel when skinning the Spaniard.
At the other end, the excellent Tom Thorpe and substitute Michele Fornasier made masterful tackles on Thomas Eisfeld and Sanchez Watt respectively but there was relief when Hayden passed up a glorious opportunity to give the hosts the lead