Daniel Udoh was the hero from the bench, netting a 108th-minute winner to break Oxford City’s resolve and ensure Town’s third-round place for the fifth time in six seasons.
Here, we take a look at some of the key talking points from Cotterill’s blue-and-amber opener.
1 Super Sarkic
What a boost it was to see the Montenegrin goalkeeper’s name on the teamsheet for the first time in more than two months after a muscle injury sustained at Plymouth in an early-season league clash. Town have had a nightmare between the sticks this season with injuries and mishaps but Sarkic, who arrived on loan from Wolves with a big reputation, lived up to his pre-injury billing again here.
Made some key saves and his distribution was decent but more impressive was his supreme handling from several high crosses.
2 Galvanised Goss
Another unexpected name on the teamsheet, the midfielder has endured a turbulent campaign, finding himself out of the registered league squad and not training with the group under Sam Ricketts.
Goss, who played in the final two cup games under Ricketts, could yet be handed a Salop reprieve under Cotterill. He needed to impress and caught the eye, with good use of the ball and a willingness to get stuck in. Needs to train hard.
3 Style switch
Almost immediately it became apparent that Cotterill’s way demanding a lot of accuracy and bravery on the ball from the goalkeeper and defenders. Sarkic passed the ball short to his back three and to midfielder Ollie Norburn on almost every occasion.
Sometimes it got away from Town and sometimes it paid off. It was clear the players, low on confidence after a tough run of form, were learning on the job after minimum training sessions and it will be that way for games and weeks to come. Cotterill’s in-game coaching will be vital.
4 Dodgy decision
Both sides finished the 90 minutes of normal time with 10 men after Aaron Pierre and James Roberts were dismissed for a coming together that looked innocent on live viewing. With the benefit of replays, it appeared Town defender Pierre was hard done by having almost taken what looked like a deliberate boot to the face from Roberts before the slightest hint of a knee towards the City man promoted a ridiculously over-the top-reaction.
After lengthy deliberation with his assistant, referee Christopher Pond sent both for an early bath. Town surely have grounds for an appeal.
5 Outstanding Oxford
The part-time visitors gave as good as they got. Having already won through four rounds to equal their best ever run in the competition, they almost created history with a place in the third round for the first time.
Prize money collected en route, coupled with the £37,500 broadcast fee, stands them in excellent stead moving forward.
David Oldfield’s men were brilliant defensively and deserved to take it to spot-kicks.
While Town had more of the ball and control of the tie as their visitors tired, City worked the opposition goalkeeper more and will now look to climb the National League South table from their position of 13th, beginning against Hungerford tonight.
6 Lots to do
It was an ideal start, in many ways. Town booked their third round ticket and Cotterill, if he wasn’t already, was left under no illusions of the scale of the task ahead of him.
The former Cheltenham, Portsmouth and Bristol City chief knows he must try to get a tune out of the side he inherited, who are lacking in confidence and belief, and down in 23rd position in League One.
But a fresh style and ethos could be just what the players needed. Cotterill must settle on to his favoured side and system, although the relentless schedule will mean changes are needed.
It was interesting to hear the boss reference fitness – or a lack of – in his post-match media duties.
He must find a way of improving fitness levels without burning out his troops.