In a timely, attention-grabbing move, Channel 4 secured impressive viewing figures on Saturday night after clinching an 11th-hour deal to screen Emma Raducanu’s historic match to British audiences for free.

Levels of public excitement about the young British tennis player’s attempt to win a her first top tennis tournament at the age of 18 had reached the level of interest that could only be compared to football’s Euro 2020 tournament earlier this summer. But, until Channel 4 stepped in, the final of the US Open was available to watch in Britain only on the Amazon Prime Video service.

The unexpected agreement to share such prominent sports coverage also comes as a well-timed intervention in the continuing debate about controversial government investigations into the viability of selling off the state-owned television channel.

Ian Katz, Channel 4’s head of content, said: “Securing Emma Raducanu’s historic match for a wide free-to-air audience is a perfect example of the kind of uncommercial but profoundly valuable public service broadcasting that a purpose- driven Channel 4 can deliver for the British audience.”

Amazon initially won the exclusive rights to televise the US Open in a deal thought to be worth about £30m. To see the final, viewers would have needed to take out a 30-day free trial or sign up to pay the monthly fee of £7.99. After Raducanu’s victory in the semi-final, the BBC was able to secure the rights to broadcast the highlights, but only to go out on Sunday afternoon. Earlier on Saturday, Katz gleefully announced the Channel 4 coup with a triumphant tweet, urging viewers to “Tear up your plans for tonight.” He pointed out the channel had also brought Test cricket back to free television earlier in the year.

Channel 4 is regarded by many in Boris Johnson’s cabinet, and by several influential Tory grandees, as an unnecessary thorn in the side, as well as a gratuitous bit of state intervention in the media sector. It is now on the point of being offered to the highest bidder. Officially, the government has said it is consulting on privatisation because it wants to ensure the long-term survival of the channel.

Charles Gurassa, the chairman of Channel 4, recently wrote in defence of its state-owned status, but the culture secretary, Oliver Dowden, has said he believes the sale of Channel 4 could be “better for the broadcaster, and better for the country”.

The government discussion document argues the “preferred option is to facilitate a change of ownership of Channel 4, which it believes will give it greater access to new strategic and investment opportunities, allowing it to compete effectively in a more agile fashion and ensuring it has the best chance of a successful and sustainable future.” Consultation about the planned sale ends on Tuesday.

Editorially independent and without an overriding profit-making mission, Channel 4 receives its funding from advertising and was set up by Margaret Thatcher’s government in 1982. Earlier this month, after four decades based in London, it opened a new national headquarters in Leeds.

Last week, a report carried out by the accountancy firm EY and commissioned by the channel found that privatisation could result in a £2bn loss to the creative sector. About half of this lost funding would be felt by regions outside London, the report argued. In terms of the numbers of actual jobs that would be supported by Channel 4 outside London after a sale, a decline of 35% was predicted. This would mean, 1,250 jobs going in each of the next 10 years.

The new research also highlighted the high probability that a switch in broadcasting priorities would follow a change in ownership. The channel’s current emphasis on breaking new talent and taking risks would be less palatable to most new commercial owners.

According to EY, a private owner could “be incentivised to prioritise mainstream content that it expects to be commercially successful to reduce costs and maximise profits”.

“Operating as a not-for-profit organisation, Channel 4 can take risks on emerging talent, acting as a first ‘big break’ for new writers and talent,” said the report.

Gurassa and Katz will be hoping the screening of a key sporting moment on Saturday night will have delivered the kind of ace public service that Dowden finds it hard to respond to.