Raising one dark eyebrow archly, and with a look of weary resignation, Gregorio Manzano dismisses the latest controversy in a season that has become exacting.

A commotion has followed the Atletico Madrid coach and his players to Scotland, something insistent and aggravating, but one of the most enduring figures in the Spanish game can only push it aside with all the other troubles of this campaign. He has encountered most of them before, and here, on the verge of an undistinguished end, he can only hold on to the notion of himself as a stately figure.

Following Saturday night's 4-1 defeat to old rivals Real Madrid, Manzano's team was accused of "roughhouse" tactics by Jose Mourinho. Not content with making a mundane accusation, the Real manager added that it was only thanks to their "carbon-fibre shinpads" that more of his players weren't hurt, Yesterday, the Bernabeu club released a medical report alleging that Cristiano Ronaldo suffered an ankle injury in the game due to heavy tackling.

"I'm past the point of caring what Real Madrid say," Manzano responded dryly. "I'm not going to pay any attention." Atletico's goalkeeper, Thibaut Courtois, and defender Diego Godin were sent off during the game and the result seemed to confirm the sense of angst that surrounding the club. The view of Spanish football journalists who gathered at Celtic Park last night was that Manzano will almost certainly lose his job if his side are defeated by Celtic in the Europa League and by Rayo Vallecano at the weekend in La Liga. Even losing in Glasgow might be enough.

Manzano is hugely respected in Spanish football, the only manager to have worked for 11 consecutive seasons in La Liga. Yet during his two decades in management he has taken charge of 18 different clubs, which tells of the vulnerability that managers face, the ever-present feeling of insecurity. His Atletico team has been inconsistent this season – losing all five away matches in the league, and only winning twice in their last nine games, but they top Europa League Group I and would secure their progress to the knockout stages with a victory tonight.

Although they lost away to Udinese, they defeated the Italian side 4-0 at Estadio Vicente Calderon, as well as briskly taking care of Celtic 2-0 in the opening match. Manzano dismisses the accusation that they are dirty, but believes his team can match Celtic in a physical sense; the tone was one of quiet, almost sombre, defiance as though all he has left to offer is his own self-respect.

"Drawing a comparison between both teams is easy," he said. "We're known to be a physical team, as are Celtic. That doesn't mean we're dirty though."

The uncertainty of his team, the notion of a side that does not know what to expect from itself, is in keeping with Atletico's recent history of faded grandeur. They are one of the leading clubs in Spain, always high profile at times in the past well resourced, but always diminished by their neighbours in Madrid. As a consequence, Atletico seem to suffer from an inferiority complex, a kind of persistent unease. Jesus Gil, the famously irascible late president, is lauded by some fans for the La Liga/Cope del Rey double the club won in 1996, but despised by others for abruptly dispensing with the club's youth set-up and forcing the 15-year-old Raul to move across the city to Real, where he became one of the game's all-time great strikers.

This duality is an essential characteristic of Atletico. They are still considered to be in a slow, deliberate rebuilding stage after two years in the second division at the start of the millennium, yet they won the Europa League in 2010. Manzano must cope with all the insecurities and the jaded air of a club still heavily in debt following the reckless spending of Jesus Gil's era. Manzano only joined last summer, on a one-year contract, then had to cope with the departures of Sergio Aguero to Manchester City and Diego Forlan to Internazionale late in the transfer window, with the club having already lost David de Gea to Manchester United.

Atletico spent £50m last summer, including £35m on Radamel Falcao, the Colombian striker who is expected to play a part at some stage tonight having recovered from injury, and £12m on Arda Turan, the Turkish attacker. Diego, the Brazilian playmaker, is also on loan from Wolfsburg. Yet the team has struggled to gel, with much of the transfer business carried out late. That haste, or feeling of alarm, still seems to exert itself.

The Spaniards will set out to win tonight – for the peace of mind of qualifying, though also to raise the club's spirits – but with an emphasis on being defensively strong and breaking on the counter-attack. It will be a pragmatic approach, with Juan Antonio Reyes, the former Arsenal attacker, left on the bench. "He does not work hard enough," said one Spanish journalist, smiling thinly.

"We're expecting a really tough game," said midfielder Mario Suarez. "They will make it difficult for us but we are ready. We have to be at 100%. We know it will be difficult, but we are ready for anything. As long as we play our own game we will come out on top."

Later, after the press conference had finished and his players were gathering on the pitch to train, Manzano appeared in the main stand at Celtic Park wearing his tracksuit and boots. He cast a glance around the stadium, then walked slowly back inside. His face was expressionless; he seemed lost to his own dilemmas.