Glentoran boss Eddie Patterson conceded his players lacked sharpness despite their home win over Ballinamallard.
The Glens players had refused to train during the week because of a dispute over unpaid wages.
They were 2-0 up inside 18 minutes through goals by Richard Clarke and David Howland, but James McKenna levelled for United in the 32nd minute.
Ballinamallard were on top in the second half but the Glens hung on for a narrow victory.
"We were flying in the first 20 minutes but then the wheels came off," said a relieved Patterson.
"The sharpness went and the fact the players had not trained was definitely a factor.
"Ballinamallard kept plugging away but we held firm for the three points."
Clarke stabbed in the fifth-minute opener from Howland's ball.
It was Howland who got the scoring touch in front of goal for 2-0 after Colin Nixon had headed the ball back into the danger area.
McKenna pounced for his first Premiership goal after the Glens had failed to effectively clear Chris Curran's corner.
Ballinamallard suffered a setback when Mark McConkey was stretchered off with a knee injury.
In the second half Glens keeper Elliott Morris made a fine save to deny Andy Crawford.