The 2021 Davis Cup Finals will be held over 11 days rather than seven and staged across three cities.
The changes were proposed by Kosmos Tennis, the Spanish-based investment firm who are pumping in $3 billion over 25 years, and confirmed by the International Tennis Federation (ITF) on Monday.
The Davis Cup – a 121-year-old event played among countries around the world – underwent a major change in 2019 as it was reduced from a season-long tournament to a one-week event.
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It will now be extended to 11 days, running from November 25 to December 5 this year.
The ITF also confirmed that two more European cities are being sought to share the staging of the 2021 Finals with Madrid, which hosted the first edition of the revamped competition in 2019. Another change is to have the Finals trimmed from 18 to 16 teams from 2022.
The 2020 edition was not played due to the Covid-19 pandemic.
"We want to make it better for the players, better for the fans and better for the teams," Kris Dent, ITF senior executive director, professional tennis, told Reuters.
"People love the idea of the best teams in the world coming together for one event, but seven days, especially the day after the ATP Finals, it's just not possible so these changes we think will make a great competition even greater."
While there was praise for the new event which ended with Rafael Nadal leading Spain to victory over Canada in the final, the logistics of playing 25 ties, each consisting of two singles and a doubles, on three courts in seven days was challenging.
One tie between the United States and Italy ended at 4am, local time.
"We believe we did a great event in 2019 but for sure there were things to improve, like the scheduling and the attendances in the stands," Davis Cup Finals tournament director Albert Costa told Reuters.

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"With the new format and the new project we have now I believe we will solve all those problems. Eleven days is better for the players because you can't play five ties in seven days."
A 10-week bidding process opened on Monday for European cities keen to join Madrid in hosting the 2021 Finals.
Turin, the new host of the ATP Finals, would be a logical option while London is another potential co-host. The two additional cities would each host two group stages and one quarter-final each, with Madrid hosting two group stages, two quarter-finals, the semi-finals and the final.
"Players we have spoken to over the last few days alone have shown real excitement at being able to add another couple of cities, making it even more a World Cup of tennis," Dent said.
"We're quietly confident we will get a good show of interest."
A final decision is expected by March based on the hosting and Covid-19 contingency proposals received from bidders.
Additional reporting by Reuters
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