Liverpool are stepping up their efforts in signing Sporting star Gelson Martins in the summer transfer window.

According to the Portuguese publication A Bola, the Reds had held negotiations with the Portuguese outfit for the winger. The Merseyside club's opening bid, which was in the region of €40m (£35m, $44.7m) to €45m (£39.3m, $50.3m) was turned down by Sporting.

Martins is wanted by the Reds manager Jurgen Klopp as they look to add more pace to their attack. The 22-year-old had an impressive run for the Sporting last season, scoring six goals and registering eight assists in the process.

His club form has seen him make it to Portugal squad for the 2017 Confederations Cup in Russia. The attacker came on as a second half substitute for Nani in his side's 2-2 draw against Mexico on 18 June.

The Portuguese international is believed to have a release clause of £50m ($63.8m) in his contract, reports the BBC. Liverpool are preparing a new bid of €50m (£43.8m, $55.9m) for Martins.

Klopp's side believe their latest bid would be sufficient for them to convince Sporting president Bruno de Carvalho to sanction the star winger's sale. Liverpool are hopeful of reaching an agreement with the Portuguese Primeira Liga outfit.

Liverpool are not the only club interested in signing Martins this summer. Another Portuguese publication O Jogo claims the Reds' arch-rivals Manchester United are also interested in landing the player.

The Red Devils manager Jose Mourinho is reportedly planning to thwart the Anfield club's efforts in signing the Sporting wideman. The former Real Madrid and Chelsea manager is an admirer of his compatriot and United have joined the race for Martins.

It should be seen whether Liverpool will be successful in beating United in signing Martins. Should Sporting accept the Reds' latest offer of €50m, the player will become Liverpool's club-record signing.

Gelson Martins
Gelson Martins is linked with Liverpool and Manchester United Getty