Kyle Neill slides in to challenge Ballymena's Kevin Kelbie

Lockhart pounced for a 12th-minute opener after Michael Halliday's header had been saved by keeper Paul Murphy.

United were reduced to 10 men six minutes into the second half when defender Gordon Simms was red-carded for bringing down Lockhart.

A minute later the Glens went 2-0 up when former Portadown player Neill scored direct from a free-kick.

Glentoran have now won 10 and drawn the other two of their 13 home matches in domestic competition since Paul Milar took over as manager.