The Australia stand-off scored and converted two tries and added two penalties in a dominant first-half performance but the Lions took control when James Hanson and Jake Schatz were sent to the sin bin late in the game leaving the Reds to finish the match with only 13 men.
During that time Courtnall Skosan scored the decisive try in the 77th minute, which was converted by Marnitz Boshoff, to snatch a late victory for the home side.
Lionel Mapoe also crossed the whitewash for the Lions, with Boshoff kicking both conversions and three penalties in total.
The game had swung the Reds' way from the off, when Cooper gave them a 3-0 lead in the second minute before he crossed for his first try in the fifth thanks to an interception, which he duly converted.
Boshoff then traded penalties with Cooper before the latter scored his second try of the game in the 32nd minute when he threw a dummy on the inside and eased home under the posts.
Cooper converted his score, with another Boshoff penalty taking the score to 20-6 in the Reds' favour at the break.
However, the tables turned in the second period with another penalty from Boshoff before Mapoe powered over after a driving maul for a converted try.
Hanson was sin-binned with 10 minutes remaining for repeated infringements with Schatz following him off for an early bath three minutes later after he cynically gave away a penalty with the Lions two metres from the try line.
The Lions went with forward power and a maul set up Skosan, who stepped inside to make the line after the ball was shipped to the left. The score was given after a check with the television match official to give the home side a 21-20 lead.
Boshoff then held his nerve to nail the conversion with the Lions repelling a final Reds charge to claim victory.
- Sports & Recreation
- Marnitz Boshoff
- Jake Schatz