France have been installed as 2/9 favourites to beat Belgium in November's Davis Cup final by Sky Bet.
France saw off Serbia in their semi-final on Sunday when Jo-Wilfried Tsonga gave the hosts an unassailable 3-1 lead in Lille with a four-set victory over Dusan Lajovic.
And Belgium then joined them, reaching their second final in three years, as they came from 2-1 down against Australia by winning both singles matches on the last day in Brussels - David Goffin and Steve Darcis the heroes.
The two nations will now meet in November with France enjoying home advantage.
With Belgium preferring to play on clay, an indoor hardcourt looks likely to be chosen by the hosts.
With that in mind, Sky Bet have the French at 2/9 to win the trophy for the first time since 2001. Belgium are the 100/30 outsiders - a similar price to the one they were offered at prior to the 2015 final against Great Britain, which they lost 3-1.
Tsonga was in an early hole in his rubber against Lajovic, who had already upset Lucas Pouille in the tie.
However, the former Australian Open finalist rallied and claimed a vital third-set tie-break to crush the Serb's hopes of another shock, eventually winning 2-6 6-2 7-6 (7/5) 6-2.
In Brussels, Goffin started the day knowing he simply had to defeat Australian number one Nick Kyrgios.
Things did not start well, Kyrgios dominating on serve before taking the opening set on a tie-break.
However, that was as good as it got for the Aussie, who had been pushed to five sets by Darcis on Friday.
Playing some excellent claycourt tennis, Goffin levelled the tie by hitting back for a 6-7 (4/7) 6-4 6-4 6-4 win.
That left Darcis and Jordan Thompson - called in to replace John Millman - fighting it out for a place in the final in the fifth rubber.
And it was the more experienced Belgian, who also won the point which took his nation into the 2015 final, who dominated.
He broke serve in the opening game as he took the first set.
The key moments came towards the end of the second set - Darcis saving two set points at 4-5 before breaking his opponent in the very next game.
He and a packed crowd in Palais 12 were soon celebrating a 6-4 7-5 6-2 victory.
"It's the final we all dream about," Darcis told the official Davis Cup website.
"We were speaking [with the French players] about this a few weeks ago and we said it would be so good if we could play against you guys, and I think they feel the same.
"It’s going to be amazing for us to be again in the final, hopefully this time we can take it home."
Goffin produced a serving masterclass to defeat Nick Kyrgios in four sets in Sunday's opening rever
In the World Group play-offs, Argentina were beaten in Kazakhstan to lose their top-tier status, just 10 months after winning the trophy for the first time.
Without the hero of that final win over Croatia, Juan Martin Del Potro, the Argentines needed to win both rubbers on the last day in Astana to keep their place in the World Group.
But US Open semi-finalist Diego Schwartzman was beaten in striaght sets by Mikhail Kukushkin in the first of them as Argentina's fate was sealed.
They will now play in Americas Zone I - effectively the second division of the tournament - in 2018.