The phrase "in the decisive round" is correct and can be used in written English.
It is typically used to describe a specific round or stage in a competition or event that will ultimately determine the outcome. Example: In the decisive round of the boxing match, the two fighters gave it their all, knowing that the winner would take home the championship title.
This Saturday, the decisive round of voting takes place to elect the next president of Afghanistan.
In the first qualifying round against Montenegrin side Budućnost, Maribor won on penalties and qualified for the decisive round against Proleter.
Bangladesh and Pakistan, two other key countries in the region in UNICEF's efforts for girls' education, also go through to the decisive rounds, as does the host nation Sri Lanka.
In the decisive second round match against Italy (only the winner was allowed to play the medal round), Germany lost, 86 84, finished ninth and did not qualify for the 2004 Olympic Games.
That election also saw Gulati in action, persuading Caribbean voters to back the Swiss candidate in the decisive second round of voting.
This weekend, as the first German to captain the 12-man team in the 25 years since its membership was expanded to include golfers from continental Europe, he manoeuvred his players into a winning position during the first two days of four-ball and foursomes play and then sent them out to face the Americans in the decisive singles round.
An alternative version has Ms Le Pen facing up against the returned Nicolas Sarkozy in the decisive second round of the 2017 vote.
Absent during most of the campaign, she did not even vote in the second and decisive round of the election.
In the second and decisive round of Brazil's presidential election on Sunday, all signs indicate that Luiz Inácio Lula da Silva, the candidate of the left-wing Workers Partyy, will coast to the victory that narrowly eluded him three weeks ago.
But the two men now facing off in this second decisive round still carry the baggage of their previous lives.
