Liverpool boss Jurgen Klopp refused to blame the defensive problems that cost his side a win over Sevilla on a failure to sign a top-class defender.
The Reds were the dominant side in their opening Champions League group game at Anfield on Tuesday but were forced to settle for a 2-2 draw, as errors and a missed penalty from Roberto Firmino proved costly.
A missed Dejan Lovren clearance allowed Wissam Ben Yedder to put Sevilla ahead and Joaquin Correa pounced on more uncertain defending to equalise in the second half after Firmino and Mohamed Salah had given the hosts a 2-1 lead.
Liverpool were heavily linked with Virgil van Dijk during the transfer window but they were forced to drop their interest after Southampton accused them of making an illegal approach for the centre-back.
Klopp has also seen his side concede a last-minute equaliser against Watford and ship five goals at Manchester City in the Premier League this season, but he insists the signing of one player would not make a profound difference.
"I know you are always looking for this thing – the defence was always something being talked about. 'We didn't sign this or that'," he told a news conference.
"If these problems could be solved by one player, you can imagine we would have put all our money into it and say: 'Let's do this'.
"It is about being dominant and losing a bit of a grip on the game in all the defensive moments. There is space for improvement. We need to learn to be dominant and not give easy goals.
"It is not a general defending problem but we have to improve 100 per cent."
Liverpool return to domestic action at home to Burnley on Saturday.