Fernandes, 21, has been one of the most discussed players available this summer following West Ham United's relegation from the Premier League. Arsenal cooled their interest earlier in the window, while Real Madrid had anticipated him joining Manchester United before Tottenham entered the picture with a more aggressive financial offer.
Sources say Spurs are "going big" on salaries for summer targets and are willing to outbid United on personal terms for Fernandes, despite finishing just one place above the relegation zone last season.
West Ham's asking price has been widely regarded as steep for a young player who has endured two consecutive Premier League relegations — first with Southampton before joining the Hammers. The Championship club are holding firm on a valuation in the region of £80 million.
United have already agreed a £35 million deal for Atalanta's Éderson and are weighing their options carefully. Chief executive Omar Berrada stressed earlier this month that the club needs to remain disciplined and not allow agents or market forces to dictate their decisions.
Tottenham have also had a bid rejected by Newcastle United for Sandro Tonali and have been linked with Marcus Rashford, whose salary at United is set to rise to £325,000 per week next month. Reports suggest Spurs would be prepared to meet those demands too.
For Fernandes, the battle now appears to be settled on wages rather than destination. United hold the appeal of Champions League football. Tottenham are offering more money. Where the Portuguese midfielder ends up may come down to which matters more to him.
Tottenham's summer spending reflects a club under pressure to move quickly after a difficult season. Their willingness to offer premium wages across multiple targets suggests a concerted effort to reshape the squad. Whether that approach proves sustainable remains to be seen, but it is making them a serious factor in several of this summer's key transfer battles.