Federer won his hometown event in Basel last month for the eighth time, beating Juan Martin Del Porto in the final.

But the Swiss star came close to exiting the tournament in the quarter-finals against Mannarino.

At 2-3 in the final set, Federer fell to 30-40 on his serve but produced an exquisite half-volley backhand down the line to save the break point.

He then came through to hold serve and then break Mannarino in the next game before eventually winning the set and the match 6-3.

Speaking after his three-set win over Marin Cilic at the ATP World Tour Finals today, Federer was invited to discuss that point.

He said: “I was in trouble there because Mannarino was doing a really nice job of hugging the baseline, playing that backhand crosscourt and I couldn’t get out of those rallies anymore.

“I needed something to happen and it was that half volley that changed the course of the Basel tournament and maybe also for me here for my confidence. 

“Sometimes it’s these margins, it’s this small. 

“People forget, only when you’re live in the stadium and you’re really this close and you see the frustration on the players face you realise how lucky or unlucky you get sometimes.”