Novak Djokovic and Andy Murray failed to qualify for the ATP World Tour Finals this year after ending their seasons early due to injury.

Rafael Nadal also withdrew with a knee problem while Roger Federer was knocked out by Goffin in the semi-finals.

It meant two tournament debutants in Goffin and Grigor Dimitrov contested the final with the Bulgarian emerging victorious after a dramatic three sets.

And Goffin believes the presence of so many newcomers in the latter stages of the tour’s season-ending tournament should serve notice to the established powers that their reign at the top of tennis is coming to an end.

“There are different generations,” Goffin said.

“There is - how can I say - not the old generation, but the generation of Federer, he's almost 10 years older than me, so we are not from the same generation.

“But he's still there. He's still playing such a nice tennis.

“You have Rafa, Djoko, Murray, all the same age.

“Then you have the next generation.”

The youngest player at the tournament, 20-year-old Alexander Zverev, qualified for two separate end-of-year tournaments but skipped the Next Gen ATP Finals in Italy for the best players under 21, which was held the week before the London event.

And Goffin was quick to point out that the players from that tournament, won by South Korea’s Chung Hyeon, 21, will make life just as difficult going forward.

“As you saw last week in Milan, there are so many good players coming,” Goffin, 26, added.

“It's going to be tough in the future.

“But me and Grigor, we are almost the same age, and we are between the generations.

“We are here in the final of the ATP Masters.

“It's our generation. But we are here and we are fighting to beat the young guns and also the old ones!”