Manchester United goalkeeper Senne Lammens has issued a scathing assessment of the team's performance in their 2-1 defeat to Newcastle United, admitting the squad had a "collective off day" at St James' Park. The loss ended Michael Carrick’s honeymoon period as interim manager, marking his first defeat since taking the reins seven weeks ago.Despite Newcastle being reduced to 10 men and Casemiro cancelling out Anthony Gordon’s opener, a late strike from Will Osula condemned the Red Devils to a disappointing defeat. Lammens did not hold back when reflecting on a result that halted United's momentum in the Champions League race. The Belgian stopper suggested the team failed to heed Carrick's warnings as they struggled to break down the Magpies."It's a really big disappointment. We knew it was going to be a difficult one... The manager warned us," Lammens told MUTV. "The first half wasn't the best but then again we were heading into half-time with a pretty good feeling scoring that goal in the last minute against 10 men."United failed to make their numerical advantage count in the second half. Lammens highlighted a lack of competitive edge as the primary reason for the downfall, noting they were outfought by their hosts. "He warned us that it was not going to be easy... the longer it stays 1-1, you know one opportunity and it can be changed. That's today what happened. Yeah, it was nowhere near good enough today in every aspect and we need to learn from that," Lammens added. The goalkeeper elaborated on the physical failings of his side, suggesting an elite club cannot afford such widespread underperformance."I mean, yeah, just like physicality, the effort," Lammens continued. "It's a collective off day which is not really possible. Not in this league, not against those teams."Add GOAL.com as a preferred source on Google to see more of our reportingWith no European commitments, United now face a break before facing Aston Villa on March 15. Carrick's side, who still sit third in the Premier League table, will travel to Bournemouth five days later."Today is a real disappointment and the feeling is really bad, but we have a couple of days and I think weeks where we need to get together and we need to think about how to react," Lammens concluded. "Starting from tomorrow, it's going to be like this and in training keep the intensity going that we can deliver in the games and then react in the next game."