Manchester United have had a £72m bid for Kylian Mbappé turned down, with Monaco wanting a world-record £100m for the 18-year-old forward.

José Mourinho has made Mbappé one of his main targets for the summer but the Ligue 1 club want to keep the teenage striker for at least another season.

United, who are also interested in Atlético Madrid’s Antoine Griezmann, have struggled in front of goal this season, although Zlatan Ibrahimovic is their top scorer with 28 goals in all competitions. The Swede, who sustained a long‑term knee injury last month, has scored 17 times in the league, with Juan Mata the second highest scorer with six.

Monaco have told United they will not sell Mbappé for less than £100m and it is highly unlikely he will leave this summer. Monaco hope his value will soar and they will be able to sell him for around £125m in 2018. The player’s preferred destination would be Real Madrid but they have yet to make an inquiry for the player who has impressed in Europe this season.

United and Mourinho are also working on other deals and have made an inquiry with Roma about Radja Nainggolan but the midfielder, who turned down Chelsea last summer, is keen to stay. Mourinho’s shortlist of signings also includes the Real Madrid midfielder Toni Kroos and Mbappé’s Monaco team-mates Fabinho and Tiemoué Bakayoko, although Chelsea are in pole position to sign the latter.

United are in danger of missing out on a top-four place in the league but are in the semi-finals of the Europa League, where they face Celta Vigo away in the first leg on Thursday. The winners of the competition qualify for the Champions League, with United well aware they may struggle to attract some of the names on their list should they not be in Europe’s premier club competition.

Mourinho could soon be one step closer, however, and has urged his players to help make club history by winning the Europa League. He emphasised his desire by saying he may rest players against Arsenal in the Premier League on Sunday. The focus at the Estadio de Balaídos will be to win a competition that has so far eluded the club. If they do so United would become only the fourth club to win all four European trophies – the Uefa Cup/Europa League, the European Cup, the Cup Winners’ Cup and the Super Cup – as well as the Club World Cup, joining Ajax, Juventus and Bayern Munich in having done so.

Mourinho said: “It is the only competition Manchester United have never won and it would be great to close that circle and say we are a club that won every single competition in the football world [sic]. I think it would be a good achievement given the [injury and schedule] problems and allow us to be back in the Champions League next season.

“We are going to try and the Europa League becomes for us more important now. Of course it depends on the result against Celta, how we analyse the game. But if we have to rest players next weekend [at Arsenal on Sunday] ahead of the return leg then we are going to do that.”

Eric Bailly is fit to start against Celta Vigo following a muscle problem and Chris Smalling and Phil Jones are also in contention. Mourinho suggested Juan Mata will play a part, possibly from the start, though the midfielder is not yet able to complete 90 minutes because of a groin problem. Yet after imploring Jones and Smalling on more than one occasion to return to action early, Mourinho again seemed to aim a dig at them when praising Bailly.

“Bailly is ready to play, he’s the kind of personality that will fight against every problem unless it’s impossible – he’s ready to play,” said the manager before confirming Luke Shaw is out for the remainder of the season with a foot injury. “Luke Shaw is injured and it’s an important injury but we are still waiting for one more medical opinion. But it doesn’t matter, he’s out for the season,” he added.