Dan Agyei’s well-taken goal sent Leyton Orient into the third round of the Carabao Cup as the League One side upset Millwall of the Championship 1-0 at The Den.

The O’s have given themselves a shot at being drawn against one of the Premier League’s big hitters in Wednesday night’s draw after comfortably holding off an anaemic Lions performance.

Agyei sent the away end into raptures by putting Orient ahead after 14 minutes when he finished clinically into the bottom corner after beating Millwall captain Shaun Hutchinson.

It was a lead the underdogs deservedly retained into half-time with the home side barely able to string two passes together, let alone threaten an equaliser.

Despite Lions manager Neil Harris making four substitutions in the first 20 minutes of the second half, his side still could not pose a threat.

It took them 76 minutes to even muster an effort on goal, with Macaulay Langstaff looping a header over after Hutchinson had kept alive a Ryan Leonard long throw.

Orient substitute Charlie Kelman had a chance to settle the game with five minutes left when he blasted a shot from a tough angle into the side netting, but one goal was enough for the visitors.