Stuart Moore said it has been a disappointing not to start the season as MK Dons' number one choice in goal.
The 24-year-old was told he was on level pegging with Lee Nicholls during pre-season after a series of promising displays last season.
However Nicholls had started all of Dons' five opening games this season prior to Moore's first appearance of the season in the 4-1 win over Southend in the Carabao Cup on Tuesday night.
Moore, who made a string of impressive saves at Roots Hall, was beaten by Brandon Goodship early in the second half as the Shrimpers sought a way back into the game, after goals from Rhys Healey and Callum Brittain put Dons in control. Hiram Boateng and Sam Nombe scored late on to secure Dons spot in the third round.
Speaking afterwards, Moore admitted: "It has been disappointing not to start the season. I know Lee is a very good keeper, so I've got my work cut out and it will be very difficult to get into the side.
"It's nice to have an opportunity to play and showcase what I can do. I had quite a busy game tonight, and as a keeper you don't always want that, but it's very important to play, and I needed to get that 90 minutes under my belt.
"I had a busier night than expected. They're a good team, caused us a few problems but we weathered the storm well, scored some important goals and we put in a good performance.
"I was more than happy to let them shoot from range, it shows how well we did defensively. It's a credit to the defenders for keeping it away from the goal. If they're going to shoot from there, I'll take it all day long."