Former world number one Andy Murray said he showed a poor attitude and did not make the right decisions in Thursday's second-round exit at the European Open in Antwerp, Belgium.

Murray, currently ranked 172nd, lost 6-4 7-6(6) to Argentine second seed Diego Schwartzman as the Briton failed to match his 2019 display when he triumphed in Antwerp -- the last time he won a singles title.

The 34-year-old, who had hip surgeries in 2018 and 2019, has not been able to get back to the kind of form that helped him win three major titles and two consecutive Olympic singles gold medals in London and Rio de Janeiro.

"Mentally, today (Thursday) I was poor," Murray said after the match.

"My attitude was poor on the court and those are two things you can control. If they're not there, that also will make the decision-making harder.

"You're not going to get every single one (decision) right in the match, but you also have to be present enough to acknowledge what is actually happening in the points and why you are winning and losing points."

Murray reached the third round at Wimbledon this year and suffered a first-round exit at the US Open.