The Red Devils, with something short of a first-choice starting XI, beat Tottenham on penalties at Wembley yesterday to lift the Carling Cup.

It was a second trophy of the campaign for the defending European and English champions, who also secured the FIFA Club World Cup title in the Far East just before Christmas.

Chelsea moved back up into second place in the Premier League over the weekend, but remain seven points adrift of Sir Alex Ferguson's side, who have a game in hand.

"I am not naive. They have a very good squad, but as long as there is a possibility, you never know. However, realistically, it will be difficult," said Hiddink, who takes his side to relegation-battlers Portsmouth tomorrow night.

"I like a team that does not give up. I liked the way the team reacted against Wigan after we conceded the goal, and that is just like I see the championship as well. We have to go as long as it is possible."

The Dutchman - who is in charge of Chelsea until the end of the season following the departure of Luiz Felipe Scolari - added: "We have the ambition to go and be [at the top] in the end of the May, so we have to stop them.

"They have always been classical clashes between two powerhouses, but let's make a few steps first."

Hiddink is impressed with the strength-in-depth United have been able to show, as the likes of England duo Wayne Rooney and Michael Carrick were left out altogether at Wembley yesterday while reserve keeper Ben Foster proved the hero in the shoot-out.

"Sir Alex Ferguson has the right blend," said the Chelsea coach.

"You have to be keen on the balance of the squad as well. You need three groups: the older group with experience, 28 to 32, some 34 the mid-group who are 23-27 and then the youngsters from 18-23.

"If the balance is right in those three groups, you can maintain your position as United have done for many years."

Hiddink has won all of his matches since taking charge at Stamford Bridge.

The Russia national team coach has been impressed by the response of the Chelsea players, who fought back to beat Wigan with a stoppage-time goal from Frank Lampard at Stamford Bridge on Saturday.

"What I see is that the players are disciplined and committed to what we want to do," he said.

"We would like to improve our control in games. Sometimes, and it is also to do with the quality of the opponents, we have struggled too much to get the game controlled and also we can improve in tactical aspects of the game.

"We have taken a maximum haul from the last few games, but there is always something we can improve on.

"I liked the reaction of the team after we conceded a late goal against Wigan. The team had the confidence first that we could do it still, then did do it.

"I hate to see a team that goes passive. The players reacted, and that is positive."

Hiddink, though, maintains Chelsea will not be complacent at Fratton Park tomorrow night.

"Portsmouth can test anyone, and Chelsea especially," he said.

"The clubs now who are fighting to avoid relegation, they are strong and they see every week that they have to gather the points, as Stoke did yesterday.

"That is difficult because the teams at the bottom have this specific English commitment.

"In other leagues, if you are second and play the teams at the bottom, it is not easy but it is easier than here. That is why they will give us a big challenge tomorrow."