Dan Matsuzaka’s second half header saw the O’s slip to defeat in the Final Third Development League this afternoon.
Skipper Mathieu Baudry and Sammy Moore were included in the starting line-up, alongside Charlie Grainger, Alan Dunne, Frazer Shaw and Scott Kashket who also got minutes under their belt.
Former Orient striker Kevin Lisbie and Antonio German were also in the starting XI as they look to earn deals with the Club.
Chances were at a premium in the early stages of the encounter, with the first chance falling to Matsuzaka but he headed wide from a corner.
From that, the O’s went straight up the other end and Kashket was played through on goal, only to see his effort just creep wide past the onrushing Ted Smith in the Southend goal.
Kashket almost turned provider minutes later, but Lisbie was just unable to get on the end of a cross from the left, and it remained goalless at the break.
Charlie Grainger in the O’s goal did well to hold a fierce 30-yard effort from Luke Prosser, and Harry Kyprianou spurned two opportunities as the half ended goalless.
Baudry and Shaw were replaced at the break by Sam Ling and Sandro Semedo, before Kyprianou forced Grainger into pushing an effort behind for a corner. From that resulting corner, the visitors took the lead as Matsuzaka rose tallest to head home.
Orient immediately went on the attack and a lovely bit of link-up play from Lisbie and German saw the latter get a shot away, only to fire it over the bar.
Moore was replaced by Victor Adeboyejo halfway through the second period and Semedo saw a fierce effort forced behind for a corner by Smith.
As time was ticking away Orient had one final chance to register a leveller and it fell to Kashket as he raced his way clear of the Southend defence, but shot wide with Smith rushing out of his goal.
ORIENT: Grainger, Dunne, Shaw (Semedo 46), Moncur, Humphrey, Baudry (Ling 46), Judd (Agyemang 50), Moore (Adeboyejo 67), Lisbie, Kashket, German.