Orient got off to a flyer in the 2013-14 season after a pulsating 5-1 victory at Carlisle United.
Much of the talking points came from an action-packed first half as Kevin Lisbie and Scott Cuthbert headed Orient into a two goal lead either side of a red card to Lee Miller for a challenge that left Orient skipper Nathan Clarke unconscious before leaving the ground in an ambulance.
David Amoo got the home side back in it from the penalty spot before the interval, but a second half header from David Mooney and two superb finishes from the returning Dean Cox sent Orient back down the motorway with three points in the bag.
Cox recovered from a knee injury that kept him out of much of pre-season to take a place on the subs bench as Russell Slade named an unchanged side to the one that started the final pre-season friendly against Arsenal on Tuesday.
New signings Marvin Bartley and Johnny Gorman were alongside Cox on the bench as Yohann Lasimant missed out as he continues to recover from a hamstring injury.
The O's almost got off to the worst possible start when Scott Cuthbert - playing on the right of defence - failed to get enough on a header back to Jamie Jones which allowed Lewis Guy to nip in and bring out the best in Jones who was at full stretch to push his toe-poke away.
Three minutes later and the O's were almost in front. David Mooney drew a foul from Danny Livesey and Lloyd James who had an impressive pre-season, curled the free-kick up and over the wall but into the side-netting from 25 yards.
After a frantic opening 10 minutes, the O's found their rhythm and came close from another James set-piece when skipper Nathan Clarke headed against the top of the bar as Orient clicked into gear.
It was gusty up in Cumbria and playing with the wind in their faces for the first half, it seemed to suit the O's as it held up in the channels for the runs of Kevin Lisbie and Shaun Batt.
Midway through the first period the O's opened their account for the season and it came from a familiar source. Nathan Clarke hurled a long throw into the box and Lisbie stooped at the front post to head home.
The main talking point of the half came on 31 minutes when Clarke jumped for a ball on the left touchline and was clattered by Lee Miller. The O's skipper appeared to land awkwardly on the hard area in front of the stand and a stretcher and immediate treatment from medical staff was sought whilst Miller was shown a red card.
The O's players and fans were extremely concerned for Clarke who left the ground in an ambulance after extensive treatment with Elliot Omozusi replacing him.
When play eventually restarted the mood had changed and the tie became an ill-tempered affair but the O's soon extended their lead on 35 minutes. James whipped in another dangerous ball from a corner and Scott Cuthbert arrived right on cue to a power a header home.
It was a pulsating half that you could barely take your eyes off and the next talking point came on 42 minutes when Carlisle broke down the left and Josh Gillies stepped inside to curl a shot against Mathieu Baudry. The O's defender's arms didn't look particularly high but the referee pointed to the spot and David Amoo rolled the resulting kick down the middle to make it 2-1.
Seven minutes of injury time were added after the lengthy delay and there was still time for Mooney to bring the best out of Gillespie with a fierce volley from just inside the box but the O's went into the interval in front after a dramatic opening first-half of the season.
The fiery atmosphere continued into the second period as despite having a man less, United toiled to get back in the game with Amoo causing problems and Liam Noble going close in the opening exchanges.
The O's would have perhaps hoped to retain the ball better at times as Carlisle continued to pose a threat despite their disadvantage.
It was on the break though that the O's extra man was becoming more apparent and on 65 minutes Batt fed the ball perfectly into Lisbie who slipped in Mooney. The Irishman opted to shoot narrowly wide from just outside the box when perhaps the unmarked Moses Odubajo might have been a better option alongside him.
As the half wore on the extra man become more apparent and Odubajo started to play a more prominent role. With 20 minutes to go the youngster steamed down the right and fired in a terrific cross for Mooney who arrived at the front post to power a header home.
There was still time for Orient to finish in style as substitute Dean Cox capitalised on some slack defending to bend an effort calmly past Gillespie with 10 minutes to go. Then in injury time he unleashed a curling effort from distance that bounced down off the bar and over the line to cap a memorable match.
ORIENT: Jones; Sawyer, Clarke (C) (Omozusi 33), Baudry, Cuthbert; Mooney, Vincelot, James, Odubajo; Batt (Cox 69), Lisbie (Gorman 83)
SUBS: Larkins, Lee, Vanderhyde, Bartley
GOALS: Lisbie (22) Cuthbert (35) Mooney (70) Cox (80, 90)
BOOKINGS: Lisbie (34) Baudry (42)
CARLISLE: Mark Gillespie, Danny Livesey, David Amoo, Liam Noble, Lee Miller, Josh Gillies (Symington 73), Mike Edwards, Brad Potts, James Berrett, Reece James, Lewis Guy (Mark Beck 73)
SUBS: Paul Thirlwell, Greg Fleming, Alex Salmon, Jack Lynch, Patrick Brough
RED CARD: Miller (31)
BOOKINGS: Berrett (9) Noble (34)
REFEREE: J Simpson