British tennis fans will be able to watch the US Open final free of charge on Saturday, after Channel 4 struck a last-minute deal with Amazon to share the broadcast of the historic match.

The grand slam final, in which British teenager Emma Raducanu will compete against the 19-year-old Canadian Leylah Fernandez, will begin at 9pm, with pre-game coverage beginning at 8pm. Raducanu, 18, is the first British woman in a grand slam singles final since Virginia Wade at Wimbledon in 1977.

Following a deal in 2018 said to be worth $40m (GBP30m), Amazon owns the exclusive UK TV rights to the US Open, meaning that ordinarily viewers would have to take out a 30-day free trial or pay a monthly fee of GBP7.99 to watch the match on its Prime service. An annual subscription costs GBP79.

Channel 4’s chief content officer, Ian Katz, said: “Emma’s meteoric rise to secure a place in the US Open Final is just sensational. We’re glad to have worked with Prime Video and pulled out all the stops to get it on air and I’m sure viewers will be thrilled at the prospect of watching Emma in this grand slam final.”

Following Raducanu’s semi-final victory, the BBC secured the rights to broadcast the match’s highlights, but only on Sunday afternoon. The public service broadcaster has the TV rights to show Wimbledon, which is protected by regulations as a “listed event”, meaning it has to be available in the UK on free-to-air TV.

Alex Green, the managing director of Prime Video Sport Europe, said the company had made a deal with the broadcaster in order to extend coverage of the historic match, adding that the giant will be reinvesting its fees from the agreement into British women’s tennis.

“Emma’s journey from qualification through to the US Open final at the age of 18 is a truly magical story for British sport and we think it’s important that we extend our coverage to as many people as possible to support her in this historic moment for women’s tennis,” he said.

The agreement with Channel 4, which is facing privatisation after four decades as a state-owned broadcaster, means tennis fans will be able to watch the match on both the channel and Prime Video. The channel, which opened its national headquarters in Leeds earlier this month, is fighting government efforts to sell it off to the highest bidder. Created by Margaret Thatcher’s government in 1982, the broadcaster is editorially independent but has always been owned by the state.

In July, the broadcaster’s chairman strongly criticised the government’s privatisation plans, accusing Oliver Dowden, the culture secretary, of failing to provide evidence to support a move that was risky and could be damaging to audiences and jobs. In a letter to Dowden, Charles Gurassa, who is due to step down in January, said the company had “serious concerns that the consequences will be very harmful, both to the UK’s creative economy and to the choice and breadth of distinctive British-made content available to UK audiences”.

The Conservatives have repeatedly attacked Channel 4, complaining that some of its output is biased against the party, leading to suspicions that there is political motivation behind the decision. While the broadcaster does not receive public funding, it is ultimately owned by the government. All profits go back into the channel, which commissions all of its programmes from independent producers.