Lisandro Martinez has criticized Manchester United's hierarchy for failing to strengthen the squad sufficiently, arguing that the pressure surrounding under-fire coach Michael Carrick should extend to the club's leadership.

The Argentina international delivered a pointed assessment of United's direction after Tuesday's 2-0 Champions League defeat to Atletico Madrid at the Metropolitano, which extended the English side's winless run to five matches in all competitions.

Pablo Barrios put Atletico ahead after just 50 seconds, while substitute Ademola Lookman sealed the victory shortly after United defender Leny Yoro was sent off, ending the visitors' hopes of salvaging a result despite a spirited response.

However, Martinez's extraordinary postmatch interview quickly overshadowed the action on the field, with the defender questioning the club's recruitment strategy and calling for greater investment from football director Jason Wilcox and the senior leadership.

"Really poor [performance], really poor," Martinez told Prime Video. "I have to control myself a lot, but sometimes it's a reflection of the mirror of how our club is at the moment."

Martinez acknowledged Atletico's quality and conceded that the Spanish side deserved to win, but argued that United had expected more support from the hierarchy after laying the foundations for a stronger team last season.

"We did a fantastic season last season and now we expect more from the top, from up, to be more players to compete because many, many teams bring many players as well," he said.

Asked whether United lacked a squad capable of competing at Champions League level, Martinez made his frustration clear.

"I expect more, honestly. I expect more (investment)," he said. "Yeah, 100%, I expect more from our technical director."

Although Martinez accepted that the players also needed to improve, he insisted that recruitment was essential to building a squad capable of competing against Europe's leading clubs.

"We have to be honest and also as players we have to do more, but it is also important when you make a strong squad to be ready for this kind of night," he said.

His comments suggested that United's struggles could not be attributed solely to Carrick, whose position has come under increasing scrutiny amid the team's poor run of results.

Martinez argued that the club needed to build on last season's progress rather than allow its rivals to move ahead through stronger recruitment. He also warned against repeatedly changing coaches without addressing problems elsewhere in the organization.

Asked about Carrick, Martinez said the coach was doing his best but stressed that opponents adapt to a team's tactics over time.

"He does his best," Martinez said. "But every season is different. You can't stay with what you did last season."

He added that rival teams study their opponents closely, making tactical evolution and squad improvements necessary to remain competitive.

"The teams know how you play, they know every detail. If you don't change, next season is a big problem," Martinez said.

The defender then questioned the club's tendency to focus on managers when results deteriorate.

"You can't keep changing, changing, changing manager. But what about other areas?" he asked.

Martinez initially appeared reluctant to elaborate, looking upward and shrugging before saying he could not say more. He then returned to the issue, suggesting that responsibility for United's difficulties extended beyond the coaching staff and players.

"Because also tonight it is easy to say the coach, it is easy to say the players, but also we have to see other areas," he said, pointing upward.

The remarks placed Wilcox and United's wider leadership under renewed scrutiny over their role in assembling a squad capable of challenging Europe's strongest teams.

Martinez's criticism also became a major talking point at the postmatch news conference, where Carrick was asked to respond to his player's comments.

The United coach said he had not watched the interview in full and suggested that the defender's frustration may have been heightened by the disappointment of the defeat.

"Well, I haven't seen the interview. I've half heard about it in the other interviews I've done," Carrick said.

"I think it's a little bit on the emotions of the game as well, coming here and being disappointed not to get something from the game."

Carrick declined to assess Martinez's remarks without hearing them directly, emphasizing instead the need for the team to focus on its next challenge.

"Straight after a game for me is not the time to talk about that interview because I haven't seen it, so I can't really comment on that," he said.

"But I think it's important for us to move forward quickly, really. I think there's a big game on Sunday, and it's really important that we move forward and we stay focused on that."

Despite his reluctance to address the interview, Carrick acknowledged the disappointment within the squad following the loss.

"There's disappointment within the group. I'm bitterly disappointed in certain things, and the boys are as well as a group," he said.