Mane ran riot against the Portuguese giants, netting a hat-trick in Liverpool’s 5-0 win at the Estadio do Dragao in the first leg of their Champions League last-16 tie.
The Reds forward was entitled to claim the match ball after the final whistle but a cheeky ball boy attempted to make off with the memento.
However, observant team-mate Robertson spotted what was happening and wrestled it back off the youngster.
The Liverpool left-back said: “I had to go running after the ball boy for his ball at the end – he was nearly upset!
“Luckily, I managed to get it. They were three class finishes from him.
“Mo [Salah] and Bobby [Firmino] have stolen the headlines in the last couple of weeks. But Sadio is on my side [of the pitch] and he is a workhouse, he works so hard. He took the limelight and got his three goals.”
Mohamed Salah and Roberto Firmino were also on target in the 5-0 win as Liverpool all-but booked their place in the last eight.
Jurgen Klopp’s side were at their attacking best and Robertson described it as the “perfect away performance”.
“We just didn’t let them settle,” he said. “Their fans tried to make it a bit hostile at the start, and we managed to quiet them very quickly.
“That’s the key to playing away. If the fans are on their own team’s back instead of ours, we’ve done our job.
“In the first five or 10 minutes we kept the ball and settled down and they let us have it. The first goal completely calmed everything down – and we never looked back.
“We were spot-on from the get-go. We were first to every second ball. We created chances and kept chances out, I don’ think they really had any clear-cut ones.
“They had a few half-chances but other than that, it was a perfect away performance. When the chances came, we took them.”