Ajax goalkeeper Remko Pasveer admits the Eredivisie champions are missing Lisandro Martinez in defence.
After appointing Erik ten Hag as permanent manager, Manchester United sanctioned a swoop for Martinez worth an initial £46.8million and the 24-year-old has been a shining light at Old Trafford this campaign. He has struck up a promising centre-back partnership with France international Raphael Varane.
Harry Maguire and Victor Lindelof deputised for those two in the Carabao Cup victory against Aston Villa last night - with Varane injured and Martinez summoned from the bench for the final three minutes. However, his absence has been felt hard back in Amsterdam with Ajax struggling to keep clean sheets since his move.
Having conceded only 19 goals in 34 games during their latest championship triumph last season, Ajax have already let in 14 goals in 13 matches this term. That does not exactly point to a leaky defence - but in the Champions League they shipped a jaw-dropping 16 goals along their way to group-stage elimination.
Pasveer, 39, spent 12 months behind Martinez in goal following his transfer to Ajax last summer. He was pressed on the United signing during an interview with Voetbal International.
He said: "Martinez was used to the Ajax style of play and put things on edge. I think that's a big loss centrally on the field as he knew exactly when to cover.
"That's something we have to learn more centrally with Calvin [Bassey]. We have to work a lot on that."
Martinez has made 20 appearances for United since his switch to the club this summer. He totted up 120 games for Ajax during his three seasons in the Dutch capital - adding six goals and as many assists - while he has been capped nine times by the Argentina national team.