Substitute Cyle Larin, returning to the side after an extended break following the World Cup, scored in the second half when he headed Ryan Manning's cross into the net.

Young Saints midfielder Romeo Akachukwu then added a second in added time at the end of the game.

This was Southampton's first competitive match since being expelled from the Championship play-offs at the end of last season.

The hosts started the game well, with Saints keeper Daniel Peretz called into action a number of times and at one stage producing a triple save to deny the U's.

Southampton were far from their best in the first half, Leo Scienza threatened at times but they struggled to produce a decisive moment in the final third.

Colchester went close in added time at the end of the first half when Jack Tucker's header had to be cleared off the line.

Saints were much improved as the second period got underway, Flynn Downes struck from outside of the box but was narrowly wide of the target.

The pressure continued to build as the half went on and they finally found a breakthrough with less than 20 minutes remaining as substitute Larin struck.

Manning delivered a cross in from the left which found Larin at the back post and he headed into the net to mark his first appearance for Saints since a memorable World Cup.

Earlier in the summer, Larin scored two goals as Canada made it to the last 16 before being knocked out by Morocco.

Colchester threatened again with five minutes to go as Harry Anderson directed a header narrowly over the bar.

Saints added the clincher when Akachukwu scored just moments after coming off the bench, his first Southampton goal at senior level.

The 20-year-old checked onto his left foot to beat a defender before calmly finishing past the keeper.

Tonda Eckert's side get their Championship season underway next weekend when they travel to take on Watford.