Summer signings Graziano Pelle and Dusan Tadic will take time to adapt to the physical nature of the Premier League, according to Ronald Koeman.

The pair arrived from the Dutch top flight as the first signings of the Koeman era, with striker Pelle joining from Feyenoord and playmaker Tadic from FC Twente.

Each player has started both of Saints’ opening Premier League matches – a 2-1 defeat at Liverpool and Saturday’s 0-0 home draw with West Brom. Tadic has looked bright in both encounters, and it seems as though he will be one of the team’s greatest creative forces this season.

Pelle, by contrast, has struggled to provide such a threat as yet.

The 29-year-old boasts a sensational scoring record from the past two seasons in the Eredivisie, and Koeman wants to see a more aggressive approach from him as he bids to bring that form to England.

“It’s difficult,” said Koeman. “I think sometimes he can be a little bit more aggressive maybe, to expect in which position the ball falls down, but he needs players from the midfield and with movements around him.

“That was the reason that we changed at half-time and we bring in Shane Long to have more speed in front. I mean, if there comes a long ball, you have to expect something.

“If you wait and you go then, sometimes you are too late.

“But for Pelle and Tadic it’s a higher level and they need to be stronger to be competitive in the Premier League. They need time for that, because it’s a big change.

“The defenders are stronger and it’s more physical than in Holland. The qualities they have, but they need time to adapt.”