It was a neat flicked finish that ultimately proved enough to secure all three points for Pompey.
Brett Pitman came off the bench at the start of the second half and converted Brandon Haunstrup’s corner to break the deadlock against Crawley.
The result meant the Blues began their defence of the newly-named competition with a group stage victory.
The strike also ensured Pitman opened his account for the season and the club captain was happy to make an impact.
He said: “It’s obviously really pleasing to come on, score the goal and get the result that we all wanted.
“The manager had told me to do what I normally do. There wasn’t really any specific message for me.
"I gambled by going across the front of my man and was able to hook it in."
“Brandon had put in a couple of really good balls just before that one and luckily it fell right for me.
“I gambled by going across the front of my man and was able to hook it in. It went in quite nicely – I’ll certainly take it.”
Pitman has yet to start a game for Pompey this term and hopes his winning goal will provide more chances to feature.
He said: “It’s been frustrating so far for me, but there are players up and down the country in exactly the same situation.
“All you can do is make sure you take your opportunity when you get one – hopefully I’ve done that in this game.
“The gaffer doesn’t need me to score in these games to show what I can do and I think my record speaks for itself.”