Erik ten Hag’s former assistant Benni McCarthy has claimed the Manchester United manager lacks some “fire” and passion” and accused a number of players of not training hard enough.

He also lifted the lid on the collapse of Ten Hag’s relationship with Cristiano Ronaldo and his belief United “wasted a great opportunity” to use the five-time World Player of the Year “in the right way”.

McCarthy spent two years working as a forwards coach under Ten Hag at Old Trafford before leaving at the end of last season following a reshuffle of the manager’s backroom staff.

United face Porto in the Europa League on Thursday and Aston Villa in the Premier League three days later with Ten Hag under huge pressure after a poor start to his third season in charge.

Scrutiny on the manager intensified in the wake of United’s abject 3-0 defeat by Tottenham at Old Trafford on Sunday.

Despite the criticism Ten Hag has received over the way he sets up his team, McCarthy said he believed the Dutchman “tactically… is at the top”.

But asked by Portuguese publication Zerozero why United have struggled to be competitive, McCarthy pointed to Ten Hag’s personality as being one factor.

Ten Hag too conservative

“In modern football, I believe that players want to see a bit more passion in their coach,” said the former South Africa striker, who won the Champions League with Porto.

“They need to feel that the coach is with them and willing to fight alongside them. Tactically, I feel that Erik is at the top. He lacks a bit of that fire, that passion. That’s where we differ, him and I.

“I want to be at his level in terms of tactical mastery. I think my greatest strength is the empathy I create with the players and that allows them to play at a level that combines passion, determination and desire. That’s how you win games, especially the most demanding ones.

“That’s the difference - that fire I feel inside me, that hunger I have. Erik is more conservative. He gives all the information to the players and then expects them to comply on the pitch.

“Sometimes I didn’t see in him that passion I spoke of. He has a different personality, a different profile. I think that was one of the difficulties that the team and the players encountered.”

Players not training hard enough

McCarthy was also critical of the application of some players during training throughout his time at United.

The 46-year-old singled out captain Bruno Fernandes and defender Diogo Dalot for praise but said others failed to meet the sort of standards set by that pair.

“If some of the Manchester United players had what Bruno and Diogo have, it would have been easier to achieve good results,” McCarthy said.

“They both trained with incredible concentration, giving everything they had. Some of the others didn’t do the same.

“This ended up limiting United’s progress, because some players weren’t training to the best of their ability.

“Even in games, the data showed us that some players were at their peak performance and others a little below. It didn’t help the team to be successful.”

McCarthy said he would discuss those poor training standards with Cristiano Ronaldo, whom he claimed could not fathom their lack of desire.

“We talked a lot about Sporting Lisbon, Porto, training details,” McCarthy said. “We talked about the mentality of those teams compared to what he saw in United training.

“We talked about the way some of our players trained… and he said that playing for Sporting, with his generation, had been the best feeling. ‘Benni, I see players now playing at one of the biggest clubs in the world and their mentality is like this. I don’t understand how they don’t have the desire to want more.’

“I understood because at Porto it was exactly like that… everyone trained to the limit. And then we were there at Manchester United, an elite club, and the level of training… we couldn’t understand it. I was very sad about what Cristiano was going through and about his departure.

“But, as I say, I wasn’t the head coach. I couldn’t be the one to make the decision to change. I had to follow Erik’s wishes.”

‘United wasted Ronaldo talent’

McCarthy offered an illuminating insight into the breakdown of Ten Hag’s relationship with Ronaldo and the Dutchman’s struggles to manage the Portugal forward.

Asked if a separation was inevitable, McCarthy said: “Yes, it was inevitable. In the end he left the club and chose Al Nassr. He is proving to everyone that he can still score goals. If we work as a team and then let Cristiano do what he needs to do in his position, because he is the best in the world at it, that is ideal.

“I think Manchester United wasted a great opportunity to use Cristiano in the right way. But I was not the head coach and I could not be the one to make those decisions.

“It wasn’t easy because Cristiano is a huge character. He has his one personality, his own maturity, and he wants a coach who understands him too. At a certain point, it’s true, things started not working out between them.

“Erik had his philosophy, his ideas and he didn’t see Cristiano being part of them. And that’s when problems started. Cristiano wasn’t happy when he wasn’t playing because he gave everything he could in training. He trains like I’ve never seen anyone train before. He’s an elite player in every way, even in his behaviour.

“He would arrive at training very early, maybe two hours before everyone else started arriving. He was the most impressive athlete I have ever met in my life. Not all athletes have what it takes to be like that. Unfortunately, the coach’s philosophy was different from what he had envisioned.

“[Ten Hag] wanted a forward who could press up front. And Cristiano believed that this work should be done by the team as a whole. With him, in some areas, the best thing to do was to give him the ball and let him do his thing.

“Cristiano saw Ten Hag opting for [Anthony] Martial and [Marcus] Rashford in the ‘9’ position and he wasn’t happy because he felt superior to all of them. The coach saw things differently.”