Liverpool defender Joel Matip admits a winless preseason hasn't been up to standards.

Jurgen Klopp's side lost 3-2 to Borussia Dortmund and 2-1 to Sevilla before drawing 2-2 with Sporting Lisbon in the early hours of Thursday morning in their final friendly Stateside this summer.

"It was an intense period with good opponents and we worked hard to get a better fitness level and to get back in the mood," Matip told Liverpoolfc.com.

"We still have a lot of work to do and we are working hard. I'm looking forward and we are confident.

"We know it's a long way to go and we still have a lot to improve, but we're on a good way."