The Dutch international moved to Anfield for £75 million (85m euros, $104m) in January, but has been on the winning side in just one of his four outings for Liverpool since.
Van Dijk got off to a dream start as he scored the winner to edge a Merseyside derby against Everton on debut.
However, hopes he would provide an instant fix to the holes in Jurgen Klopp’s defence were shattered in back-to-back shock defeats to Swansea and West Brom.
“I know because I made such a big step right now, for a lot of money, everything is going to be analysed,” said Van Dijk.
“No one is going to look at the good things that you do. Everybody is going to watch the bad things and that is how it is. But I will discuss it with the people who want to make me better, who can make me better, that is the manager and the players around me.”
Yet, there were signs of why Liverpool waited to get their man in January after an initial move for Van Dijk stalled last summer in last weekend’s 2-2 draw with top-four rivals Tottenham Hotspur.
Van Dijk during his days at Southampton
Van Dijk largely kept the Premier League’s top scorer Harry Kane quiet until a frantic finale in which Spurs were awarded two controversial penalties – the second of which for a foul by Van Dijk on Erik Lamela in virtually the last action of the game.
“No one will talk about my performance in general. We defended very well, had two penalties against us with a lot of question marks around them, but no one is going to talk about that,” added Van Dijk.
“But I know that as a team we did very well against one of the best strikers in Europe.”
Both teams are in need of the points at different ends of the table. Third-placed Liverpool can gain more ground in the race for a Champions League place, whilst Southampton are still precariously positioned just two points above the relegation zone despite a first league win since November last week at West Brom.
However, Van Dijk insists he will have no sympathy for his former employers on Sunday.
“I made the decision, I have enjoyed every bit of it and I am very grateful for everything that they did for me. I have moved on, they have moved on.
“I know they are struggling and we need to win. I am going there with only one mindset and that is to win.
“Obviously it will be nice to see the players I have played with and the friends I have there but, for me, it is going to be about one thing only and that is to win the game.”
Jurgen Klopp is expecting big things from Van Dijk.
Liverpool return to the European stage on Wednesday when they travel to Porto for the first leg of their Champions League last 16 tie, but Klopp, who has rotated his side more than any other manager in the Premier League this season, struck down suggestions his team selection would be affected by preparations for the trip to Portugal.
“I have a few experiences with European football and I never thought about the European game the week after,” said the German.
“The main focus is always the next game, in this case Southampton. You cannot and we will not think about the Champions League game.”