Leyton Orient bowed out of the Carabao Cup at Championship club Plymouth after a first-half brace from Ben Waine.

Richie Wellens made five changes from Saturday's League One opener at Charlton, with Sam Howes making his debut in goal in place of Sol Brynn.

Jordan Brown, George Moncur, Ethan Galbraith and Jordan Graham also came into the line-up after making appearances off the bench at The Valley, as Jayden Sweeney, Theo Archibald and Idris El Mizouni were named among the substitutes and Darren Pratley was left out of the matchday squad.

And O's had a let-off on seven minutes when Freddie Issaka saw his shot pushed out by Howes into the path of Ben Waine, who tucked the ball home from six yards only to see the offside flag raised.

The visitors saw a promising attack come to nothing soon after as Graham lost control just outside the box and was penalised for a foul on an Argyle defender, with Moncur hoping for a pass to his left.

Argyle found the net again on 17 minutes, with Finn Azaz sliding home a right-wing cross from close range, but the offside flag was raised once more to spare O's.

But the east Londoners then hit the woodwork twice from the same corner moments later, as a Plymouth defender headed against the far post before Beckles thudded the rebound against the crossbar.

Brown was shown the first yellow card of the night for a trip on former Arsenal youngster Julio Pleguezuelo, Argyle's captain, in the centre circle, before a strong Tom James challenge freed Ruel Sotiriou, who teed up Joe Pigott for a shot pulled just wide of the post.

Argyle opened the scoring on 25 minutes, though, as Beckles was punished for a poor back pass by Waine, who slid the ball beyond Howes.

But Howes held onto a firm blast from Issaka moments later, before Tyreik Wright's long range effort was also pouched.

O's got a couple of sights of Callum Burton's goal as Galbraith fizzed a rising drive over from 25 yards from a James corner, before Moncur curled a left-footed effort beyond the far post.

But the hosts doubled their advantage seven minutes before the break when Issaka found space on the left and saw his cross deflected into the net by the body of Waine at close range.

Graham made way for Archibald during the break, with Sotiriou picking up Orient's third yellow card of the night soon after the restart.

Luke Cundle received Plymouth's first caution for pulling Sotiriou back moments later, but O's could not make the free-kick count and were forced to play the ball all the way back to Howes by the home side's press.

Archibald sent an ambitious free-kick from wide on the right narrowly over the crossbar on 55 minutes, with Pigott seeing a shot on the turn deflected behind.

Dan Happe made way for Sweeney just before the hour, after going down and having some brief physio treatment, with James moving into the centre of defence and Rob Hunt switching to right-back to accomodate the new arrival.

And Richie Wellens made a double change midway through the half as Moncur and Sotiriou were replaced by Charlie Pegrum and El Mizouni.

The fifth and final change of the night saw Pigott withdrawn for Zech Obiero, after a hard-working display as the lone O's striker for the most part, and El Mizouni had a shot comfortably saved by Burton from the left corner of the box.

But the visitors struggled to seriously test the home keeper on the night and had to replace Galbraith late on with Harrison Sodje, for his competitive debut, after the midfielder picked up an injury.

And with Portsmouth visiting Brisbane Road on Saturday, there would have been plenty for boss Wellens to ponder on the long journey back home from Devon.

Leyton Orient: Howes, Brown, Happe (Sweeney 59), Beckles, Hunt, Galbraith (Sodje 85), Moncur (El Mizouni 66), James, Sotiriou (Pegrum 66), Graham (Archibald 46), Pigott (Obiero 72). Unused sub: Brynn.

Booked: Brown, Pigott, Sotiriou, Obiero, Sodje.

Attendance: 10,324 (including 147 Orient fans).