Maya Yoshida says Saints must improve their defensive resilience in the wake of today's 3-1 loss at Everton.
Things looked to be heading in the right direction on the Japanese international's third start for his new club after Gastón Ramírez put them one up after six minutes.
But three Everton goals in the space of 13 first-half minutes left Nigel Adkins' team with a mountain to climb against an impressive Toffees side.
And Saints could not produce a second-half showing like the one seen in the excellent win over Aston Villa a week ago as the game ended 3-1, leaving Yoshida disappointed.
"We need some improvements, especially defensively from crossing," he told Saints Player after the game.
"We made too many mistakes today – it was too easy to lose the ball in midfield so we have to change this.
"We lost too quickly and too easily today, I think."
Nevertheless, Yoshida said he was generally pleased with how his centre-half partnerships with José Fonte and Jos Hooiveld are developing.
"I think we are improving with every game," he said. "I'm always talking to José and Jos – and them to me, as well. The combinations are getting better.
"I now understand how to play with everyone, and I can also show my performances are getting better.
"The gaffer expects me to play good balls out in front, and to control the game by keeping the ball.
"Today it is important in football to bring the ball out from behind so I want to show more quality."