Mario Lemina keen to prove his worth after joining Southampton

The 23-year-old Gabon midfielder has put pen to paper on a five-year contract with the Saints, a transfer which Juventus confirmed was worth 17m euros (£15.6m) and could increase by a further three million euros (£2.77m).

Lemina helped the Bianconeri win the Serie A title as well as reach last season's Champions League final against Real Madrid, and had been linked with a number of clubs before completing his switch to St Mary's Stadium under new manager Mauricio Pellegrino.

Saints kick off the new Premier League campaign at home to Swansea on Saturday, and Lemina hopes to be able to hit the ground running.

"I think I can bring to this squad, whether it be offensively or defensively, my power and ability to defend and get things moving forwards. I n that way, I can give my very best for the team," he said in an interview with Southampton's You Tube channel.

"I have a lot of friends from France who are here and have explained to me what it is like to play in the Premier League.

"I know the Premier league is a different league and I hope that I can adapt quickly to it because I know that it is a league where everything goes quickly."

Lemina added: "T he aims are the same as they were last season - to finish high up the table, whether that be sixth, seventh or eighth. Why not challenge for the Europa League?

"As I have seen, the club is very ambitious and we want to stay on this upward path".

Lemina started his career in France with Lorient before joining Marseille in 2013 and initially signing on loan with Juventus in 2015, ahead of completing a permanent transfer last summer.

Southampton vice chairman Les Reed feels Lemina will be a welcome addition to Pellegrino's squad, which has also been bolstered by Poland Under-21 defender Jan Bednarek.

"Investing in a player of Mario's quality and buying from a club like Juventus is a significant statement of intent from the club, and this is a purchase that has set another club-record fee," Reed said.

"Mario still has his best years ahead of him, and we believe that he will not only be an excellent acquisition for us in the immediate future, but that he will also be able to realise even more of his potential here in the years to come."

While Pellegrino has been busy fine tuning the players for the start of the new Premier League season, the future of defender Virgil van Dijk remains unresolved.

On Monday evening, the Dutchman hit out at his treatment from Southampton as he made public his intention to leave St Mary's.

The 26-year-old said he felt ''insulted'' by suggestions he had refused to train and has grown frustrated at the Saints turning down approaches from ''multiple top clubs'' this summer.

The Holland defender, who joined the club from Celtic in 2015 and is a long-term target for Liverpool, revealed he had handed in a transfer request.

Van Dijk was left out of the Saints' pre-season training camp in France last month, with Pellegrino saying ''psychologically he is not 100 per cent'', while Southampton have insisted he is not for sale.

In a statement released by his management company, Van Dijk said he had not refused to train at any time and that his desire to leave owes to his ambition to challenge for trophies.

"I want to play European football again and challenge for major honours and as such I would like Southampton to consider the interest in me from top clubs should it still exist," he said.

''I have been left frustrated by the club's position that I am not for sale and am disappointed that enquiries from multiple top clubs have been consistently rebuffed."