Leyton Orient stunned Carlisle United with an incredible first-half goal blitz as they thrashed them 4-1 at Brunton Park.

Orient grabbed the opener through David Mooney although the hosts equalised from a Peter Murphy header.

But the visitors immediately restored their lead through Ben Chorley before Lee Cook made it 3-1. Mooney's second of the match came just before half-time to leave both sets of supporters shellshocked for contrasting reasons.

Orient were under no real pressure in the second half as they eased to their third win in the space of a week and set themselves up perfectly for the midweek trip to Portsmouth. 

The O's made four changes from the side which won at Gloucester in the FA Cup on Wednesday night. Kevin Lisbie returned up front in place of Ryan Brunt while Martin Rowlands started ahead of Anthony Griffith.

Cook also slotted back into the midfield ahead of Jimmy Smith while Chorley returned to the centre of defence in place of Mathieu Baudry. 

The visitors created an early opportunity after seven minutes when Cook floated in a cross but Lisbie was stretching for the ball and unable to get a decent connection to divert it towards the goal.

Carlisle threatened the O's goal for the first time when John Paul McGovern sent in a cross but Liam Noble's header was straight at Ryan Allsop.

Orient took the lead after 18 minutes when Dean Cox sent in a cross and Mooney's header struck the post. But the forward followed up to fire in the rebound from close range and net his second goal in four days. 

United grabbed an equaliser in the 25th minute when Murphy rose to head home from McGovern's free-kick.

Incredibly Russell Slade's side regained the lead within 60 seconds as they stunned the hosts with a scrambled finish inside the area from defender Chorley. 

It could have been 3-1 to Orient when Cook fired in a free-kick which crept just past the post with goalkeeper Adam Collin well beaten. 

The visitors did not have to wait long for their third goal as Lisbie broke away and his pass fell perfectly for former QPR winger Cook to tap the ball into the net.

Orient had scored three times in the first 40 minutes which was almost unbelievable considering their struggles in front of goal all season. 

Slade's side were looking dangerous every time they attacked, against a shocking Carlisle defence, and incredibly added a fourth goal before the break.

Mooney was released by Lisbie and the striker showed real conviction and confidence as he struck a fine effort into the net to the delight of the 113 travelling fans. 

This brought an end to an astonishing first half as the home supporters vented their anger with a chorus of boos. 

Carlisle boss Gref Abbott made three substitutions at the break knowing his side need an immediate response to have any chance of getting back in the match. 

The hosts created an opportunity from Matty Robson's cross but Joe Garner's volley was straight into the arms of Allsop. 

It was so nearly a hat-trick for Mooney when he struck a superb effort which cannoned off the crossbar. 

Slade made his first substitution when he introduced Griffith in place of Lloyd James. Orient also brought on Michael Symes in the last 15 minutes for the excellent Lisbie.

The visitors made their final change of the game with Smith replacing the impressive Cox in the last ten minutes.

It was a very comfortable second half for Orient and they easily saw out the match equalling their biggest win of the season with a superb three points on the road. 

Carlisle United: Collin; Simek, Murphy, Edwards, Chantler; McGovern (Robson, HT), Noble (Beck, HT), Potts, Berrett; Garner, Higginbotham (Symington, HT)

Subs not used: Welsh, Todd, Gillespie, McGinty

Leyton Orient: Allsop; Sawyer, Chorley, Clarke, Odubajo; Cox (Smith, 83), Cook, Rowlands, James (Griffith, 64); Mooney, Lisbie (Symes, 76)

Subs not used: Jones, McSweeney, Baudry, Brunt

Referee: T Harrington

Attendance: 3,964