For 45 minutes of this game, Fabio Vieira looked like he wanted to be anywhere else other than the Kassam Stadium.
Vieira was one of the biggest victims of that and more than once he ended up in a heap on the floor.
On one such occasion centre-back Rob Holding urged the 22-year-old to get up, while another time Vieira yanked off his gloves and threw them off the pitch.
At 0-0, and with neither side having a shot on target, the second-half was a moment for Arsenal, and particularly Vieira, to roll their sleeves up and the Portuguese midfielder inspired them to a 3-0 victory.
He finished the game with two assists and it was a remarkable turnaround from a player who was a passenger in the first-half.
Arteta had spoken this week about how Vieira is ready to make an impact for Arsenal and, even if this was only League One opposition, this performance will have done the youngster the world of good.
He has so far failed to live up to the hype after his £34million move from Porto this summer, but a disrupted pre-season and playing in rotated teams has not helped his cause.
The latter was apparent here at Oxford as Arteta made seven changes to his starting XI ahead of Sunday’s trip to Tottenham.
The front-three were among those to keep their places - a sign of how short Arsenal are for attacking options - but they created nothing in the first-half. The only highlight was a penalty shout for handball and the Oxford fans having a great time singing: “Boring, boring Arsenal!”
The second-half was a different story, though, and Arsenal set the tone by coming out early, with manager Mikel Arteta’s words no doubt ringing in their ears.
Whatever the Spaniard said it seemed to do the trick. First, Vieira gave Arsenal the lead by swinging in a brilliant free-kick for Mohamed Elneny to head home. That goal came in the 63rd minute and by the 74th it was game over.
Vieira was at the heart of it again, carving open the Oxford defence with a lovely pass that found Eddie Nketiah. The striker rounded the goalkeeper and finished with ease.
Moments later, Nketiah had his second and Arsenal their third. This time it was Martinelli who got the assist, but Vieira was involved in the build-up.
A memorable night for the midfielder when it had looked set to be a forgettable one. Manchester City await in the fourth round, when Vieira will really have a chance to make an impression.