Dundee United boss Ian McCall said his side were undone by Motherwell's two-goal hero Scott McDonald, who he once thought was too "heavy".
"His second goal was a joke goal from our point of view. But he's a good player, no doubt about that," he said.
"I tried him at Tannadice but, I think he would tell you himself, he wouldn't have advised us to sign him when he came to the club.
"He was a little bit heavy but fair play to him, he's done really well."
McDonald added: "I wasn't the fittest when I went to United. I had just come back off holiday. But there was no extra incentive for me to score against them.
"They were great to me, and wanted me to come back a week later, but I didn't want to stay around. So I went back down south and signed for Wimbledon.
"You never know what could have happened, but it's just great to score goals no matter who it is against.
"But I really enjoyed myself at Southampton, and I'd like to return to the Premiership one day."