Erwin Koeman has warned Saints they will have to cut out the errors in possession they showed against Vitesse when they kick-off their Premier League campaign at Newcastle.

The Saints assistant manager was naturally pleased that his side sealed their passage through to the Europa League play-off round with a 2-0 win at Vitesse last night, which gave them a 5-0 aggregate victory.

But he also warned that mistakes on the ball would be punished when Saints do not start with a comfortable lead at St James’ Park on Sunday, He said: “We were happy with the (first) goal because it’s all about the result and going on in the Euro League so for us it was a fantastic start.

“The rest of the game we defended very well.

“They had some shots outside the 18 yard box but I think in ball possession we did not play a good game. We have to improve more, especially for Sunday.

“We can do better and we have to do better.

“For some players it is sometimes difficult to get focus on the game and maybe they are thinking not so fast playing, a little bit slow, and then you get problems.

“We defended well so that’s a good point.

“After four minutes it’s 0-1 and then they have to score five times. Almost impossible.

“Some of the players, especially when we have ball possession, they were sloppy but, ok, Sunday you get big problems. Now not because after the 0-1 for them it was impossible to come back to make five goals.”

The Europa League experience, and playing twice in quick succession, is still a learning experience for Saints, but Koeman will not take any excuses.

“It’s nice because we play last year the whole year for European football,” he admitted. “Finally you get European football and we may not complain about playing Thursday, Sunday, Thursday, Sunday because that’s what we want. No excuses.

“We have older players in the team, who are experienced players and they know, and some young players and for them it’s maybe a bit different.

“If you want to survive in top football you have to do more and you have improve yourself, we have to improve ourselves.”

He added: “I think our supporters were amazing like last week the Vitesse supporters and of course they are looking forward to the draw as we also, and then going to Newcastle and it starts on Sunday.

“We are looking forward to going to Newcastle.”

The game against Vitesse saw a competitive debut for Steven Caulker and Koeman reflected: “He did well. He was defending well. He played against a very good striker, a quick one.

“It makes it difficult but he did very well in the first half, he had one or two moments he had difficulties but overall he did very well. He did a good job.”