Gillingham claimed a win at Priestfield to seal their League 2 safety in a match that was held up by a power cut.

Alex MacDonald put Gillingham ahead from a free-kick after visiting defender Omar Beckles had been sent off for a professional foul early on. Cheye Alexander added a second from the penalty spot before the lights briefly went out at Priestfield. Leyton Orient’s promotion was confirmed before play resumed.

Gillingham lined up unchanged from the team who started at the weekend against promotion-seeking Stockport. Neil Harris’ men impressed in a 1-1 draw and it meant returning striker Oli Hawkins had to make do with a place on the bench.

It looked like it might have been a long night for the Gills as Orient started the game in control, passing the ball around well and limiting the hosts to very little. It all changed with 14 minutes gone.

A long punt forward from the Gills keeper Glenn Morris was flicked on to George Lapslie and when he burst through on goal, defender Omar Beckles’ decision to take him down led to an early dismissal.

Orient were a man down and Gills made them pay from the free-kick too as MacDonald whipped it into the bottom corner to compound the visiting side’s frustration.

The league leaders were losing the plot as their captain Darren Pratley went into the book for a foul and the manager Richie Wellens was cautioned by the referee for dissent. Forward Paul Smyth also picked up a yellow card for a foul.

Shortly after the goal the Gills got into another good position, when Tom Nichols played Dom Jefferies in down the side but the shot was high and wide.

Orient’s early dominance had evaporated as the Gills dictated the tempo for the rest of the half. Rob Hunt was also booked before the break as he swung a wayward elbow in Nichols’ direction.

A free-kick late on might have led to something for Orient but Tom James’ effort went just over, helped on by home keeper Morris. Gills were awarded a goal-kick, a decision that further annoyed the visitors.

It was supposed to be Orient’s promotion party but they went off at the break furious with referee Carl Brook. Wellens ushered his men away from the official as they went off at half-time, only to direct some more choice words of his own to the under-fire ref.

Nichols came close to extending Gillingham’s lead with an early header in the second half but a super one-handed save from goalkeeper Lawrence Vigouyroux denied him.

Gillingham were able to knock it around at the back without any pressure and it prompted changes for the Os on the hour.

Orient were handed a chance to get back in it with a free-kick from just outside the box after Shaun Williams had been harshly penalised for a challenge on Smyth. James’ free-kick couldn’t beat the Gills wall, however.

The visitors started taking more risks as the game progressed, opening things up.

The Gills added a second goal in the 76th minute from the penalty spot. MacDonald’s free-kick was handled in the box and Alexander stepped up to score.

Celebrations were on hold as the lights went out at Priestfield with 10 minutes left. During the powercut a goal for Swindon against Bradford led to joy in the away end as promotion was back on the cards.

The players left the field as efforts were made to restore power to the floodlights which eventually happened with a 23-minute delay. By the time play restarted Orient’s promotion was confirmed thanks to Swindon’s win over Bradford, prompting wild celebrations on the pitch before kicking off again.

Gillingham restarted play by knocking the ball around at the back. Nobody seemed interested in playing, on in what was a bizarre end to the night. The Gills were staying up, Orient’s promotion was confirmed, and the final few minutes were a non-event, with the referee blowing full-time a minute early.

Gillingham: Morris, Alexander, McKenzie, Ehmer, Masterson, Williams (Coleman 74mins), Dieng, Jefferies, MacDonald, Lapslie, Nichols (Hawkins 71mins). Subs not used: Turner, Tutonda, Wright, Clarke.

Leyton Orient: Vigouroux, James, Smyth (Kelman 77mins), Sotiriou (Drinan 60mins), Moncur, Mizouni, Pratley (Brown 60mins), Beckles, Hunt, Sadlier (McCart 20mins), Turns (Ogie 77mins). Subs not used: Sergeant, Clay.

Referee: Carl Brook

Attendance: 6,629 (1,651 away)