West Ham are battling to convince Celta Vigo’s Maxi Gómez to snub Champions League football at Valencia and join them for a club-record fee of €50m (£44.5m) after selling Marko Arnautovic to Shanghai SIPG for €25m.

After intense negotiations over the weekend West Ham are still in with a chance of winning the race to sign the highly rated striker – a race they feared they would lose as late as Sunday evening. They have agreed to pay Gómez’s release clause and are now trying to persuade the Uruguay international to choose a move to the Premier League over staying in Spain and joining Valencia.

Manuel Pellegrini, West Ham’s manager, has prioritised the signing of Gómez ever since Arnautovic first started trying to force a transfer to the Chinese Super League in January. Yet the highly coveted 22-year-old has repeatedly indicated that he favours Valencia, even though they are offering him lower wages.

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Valencia finished fourth in La Liga last season, earning them qualification to the Champions League, and the lure of playing at the highest level seemed to have informed Gomez’s decision. It is understood they had agreed a €16m deal which would have also involved them sending Santi Mina to Vigo. They thought the transfer was all but done last Friday.

Yet West Ham, who had already released Andy Carroll and sold Lucas Pérez to Alavés, stepped up their pursuit of Gómez after deciding to let Arnautovic move to China when the Austrian forward kicked up another fuss last week. Pellegrini told the board to sell Arnautovic for the sake of squad morale and wanted the transfer to be concluded swiftly enough to ensure the former Stoke City player did not have to report for pre-season training in Switzerland on Monday.

The decision to get rid of Arnautovic leaves a hole in West Ham’s attack, forcing them to respond quickly and decisively. With Arnautovic following Carroll and Pérez out of the door, the only senior strikers on their books are Javier Hernández and Jordan Hugill, who has made no impact since joining from Preston North End in January 2018 and spent last season on loan at Middlesbrough.

They are also likely to miss out on another of their targets, West Bromwich Albion’s Salomón Rondón. Rafael Benítez wants the Venezuelan striker to follow him to China and join Dalian Yifang. West Ham also believe that Andrea Belotti, rated at €70m by Torino, is too expensive. That leaves them to focus on Gómez.

When West Ham had a £25m bid rejected for him last month their information was that Gómez, who has scored 30 goals in 71 league appearances for Vigo, wanted to play in the Champions League, giving Valencia the edge. When they decided to hijack Valencia’s bid on Friday, they were told to raise their latest offer of £40m.

Gomez’s contract contains a €50m (£44.5m) buyout clause and West Ham were told they would have to trigger it to stand any chance of signing the striker. With their funds boosted by the sale of Arnautovic, they offered that amount late on Sunday night, albeit they have yet to agree whether to pay the fee in one lump sum or in separate instalments.

However, they still have to convince Gómez that joining a side that finished 10th in the Premier League last season represents the best move for his career. Sources close to the deal say it is finely balanced and rate West Ham’s chances of clinching it at 50%.

West Ham have made three signings this summer. They have recruited two goalkeepers on free transfers, David Martin and Fernando, and raised excitement with the £24m signing of Pablo Fornals from Villarreal. The attacking midfielder helped Spain to win the Under-21 European Championship last month.