DIDIER AGATHE last night delivered a withering verdict on his former club Celtic by accusing them of failing to commit themselves to the investment required to become bigger and stronger during Rangers’ absence from the top flight.

The former winger, who won three league titles and played in a UEFA Cup final for the club, believes they should have ploughed resources into the squad when their Glasgow rivals went into administration in 2012 in order to ensure that their status as the dominant club in the country was well-established by the time Rangers had earned themselves a place in the Premiership.

Instead, he believes that the decision to downsize has meant that Celtic have missed an opportunity to put themselves out of reach and finds it incredible that they are still locked in a battle for the championship with Aberdeen with just six games remaining.

Aberdeen travel to Hearts this evening in the knowledge that a victory would close the gap at the top to two points with Celtic facing a precarious trip to Motherwell on Saturday.

“They should be bigger and stronger than they ever were,” said Agathe, who was signed for Celtic by Martin O'Neill in 2000. “They had a chance to make themselves the biggest club in Scotland for a long time, but, instead, they have tried to not spend so much and you can see what the difference is.

“They should be out of sight from everyone else by now.

“If they had spent money, they knew that they would have a chance of European football every season. With quality players, you can make a mark there. Instead, over the last few years, the quality has not been there to do that.

“It would be a disaster if they do not win the league this season for everyone, but they should never be in this position.

“I love Celtic. I am a Celtic fan, I loved playing with the club and being a Celtic player, so I always want them to be successful and to win. But these last few years should have made them bigger, much bigger, than any other club in the country.

“You have to ask the question – can you expect to have a successful and winning team at the top level if you do not spend money? You need to invest in the right quality of players to get the results that everyone expects from Celtic.”

Agathe was part of the 2005 side which lost the league on the final day of the season at Fir Park immediately prior to O’Neill’s departure from the club. However, he has dismissed comparisons between the current Celtic side and that squad.

“Losing the league that day was awful, but I don’t think you can compare it to now,” he said. “We had played many games in Europe as well as domestically that season. We had been in the group stages of the UEFA Champions League and we were up against a Rangers team that was full of internationalists. They had pushed us all the way.

“Celtic now do not have that. If there is no Rangers in the league, they should be winning the title. Without question.”

Agathe understands that an Aberdeen win this evening would really raise the temperature ahead of Celtic's latest visit to Fir Park, but he insists there should be no question of the players coping with that.

“Pressure should not matter,” he insisted. “When you sign for Celtic, you sign for a club that has won the European Cup. You know what the club is all about and you know the size of it. If you don’t it does not take long to get the message.

“You sign for Celtic to win titles. To win Cups, to make a name for the club in Europe. The minute you pull on your boots to play for the club, you know immediately what you are there to do.

“If you have the right quality of player, they will thrive on pressure. They do not shrink under it. To me, that is the question now – is the quality there? It is up to them to show it.

“They should not feel pressure when it is a league without Rangers because they are so far in front of everyone else.”

Agathe has welcomed Rangers into the Ladbrokes Premiership after Mark Warburton’s side clinched the Championship this week, insisting that the profile of the Scottish game is giving a fresh injection with their involvement. He also believes that the Ibrox side are in a strong position going into next weekend’s Scottish Cup semi-final at Hampden.

“I think that game next weekend is 50-50 and we should not be saying that,” he said. “If this is a team who win the title playing a team from the lower league, it should be straightforward, but I think that Rangers now have the confidence and Celtic are in a position where fans are not happy with the way the team are playing.

“Scottish football needs that rivalry. It is a rivalry that is known throughout the world and it causes people to look at it, to want to watch games between the clubs."