Martin Skrtel believes having healthy competition for the centre-back role is an excellent way to prepare for the demands of the new season, and has welcomed the return of Mamadou Sakho.

The French international joined back up with the squad after his World Cup exploits, and took part in the squad's first training session in Chicago as the Reds prepare to take on Olympiacos as part of the Guinness International Champions Cup.

After having parts of his debut season disrupted by injury, Skrtel believes the imposing French defender would have gained vital experience in preparation of the new campaign.

"It is good to have Sakho back because he's been out for a while," Skrtel told Liverpoolfc.com. "Now the squad is together and we are all getting ready to start the new season.

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"Now he knows what to expect in the Premier League and English football, he will carry on with the hard work he's been doing and show some good performances next season."

As well as Skrtel and Sakho at centre-back, the Reds also have Daniel Agger and Sebastian Coates pushing for what is normally only two positions in the team's starting XI, highlighting the intense competition for places in Brendan Rodgers' squad.

He added: "It's even more with Kolo [Toure] and Tiago Ilori as well, so there's going to be competition for the two places and everyone wants to play, but only two players can start.

"I think it's only good for ourselves because it pushes us to work hard in every single session - then it's up to the manager who is going to play."

Liverpool's No.37 also spoke about the training sessions the Reds have endured whilst touring North America in a bid to get everyone at maximum level for the start of the new campaign.

He added: "It was quite hard because there's a lot of running, but that's what pre-season is all about; just trying to get fit. Now we're about to start this tournament so we're looking forward to that because every single player prefers to play in games [rather] than train.

"I hope [my fitness is] good, I played 90 minutes against AS Roma and I felt a bit tired after that but like I said, pre-season is about hard work and getting ready for the next season and to try to be ready for the first game."

It's Olympiacos next up tonight for Liverpool, and Skrtel is welcoming the added intensity which comes from playing matches in a tournament setting, such as the Guinness International Champions Cup.

He added: "Roma was a friendly game but now we're starting to play this tournament which is a good competition because it's not only a friendly game; we'll try to get a result and try to win the tournament so I think it's a good way to prepare for the season.

"Obviously, the stadium is very nice and it's going to be full - the people will create a great atmosphere."