Carlo Ancelotti played down a spat between John Terry and Didier Drogba, two of his senior players at Chelsea, as the defending champions lost further ground in the Premier League title race after a thrilling 3-3 home draw with Aston Villa.

Chelsea had rallied from 2-1 down to lead 3-2, courtesy of Terry's last-minute goal, only to switch off in injury-time and allow Ciaran Clark to claim a dramatic but deserved equaliser for the visitors.

Drogba argued with Terry as they left the field, with Chelsea struggling to comprehend how they could have conceded such a soft goal. Marc Albrighton, the Villa substitute, was given time to cross and Clark stole in between Terry and Ashley Cole to glance home.

Chelsea remain in fifth place, but are six points behind the leaders Manchester United, who have a game in hand over them. Ancelotti's team have taken just 10 points from an available 30 to slip from their perch at the top of the table.

"Everything is OK in the dressing room," Ancelotti said, as he sought to accentuate the positives from a brighter second-half performance. "We've lost confidence but not our winning mentality because our bad moment has been too long. I think that in the last game [the 1-0 win over Bolton Wanderers], the play was good. Obviously, we have to improve but I think we are improving."

Ancelotti was forced to field a makeshift partnership in the centre of defence, with the 19-year-old Jeffrey Bruma making his first league start alongside Terry, in the absence of the injured Alex and the suspended Branislav Ivanovic.

"Defensively, we lost something, obviously," Ancelotti said. "I just want to say that Bruma played very well but without Alex and Ivanovic, we lose some energy on the high balls. We conceded the second goal for this reason. The third was different because we needed to have more attention in the box."

Terry's goal had been the prompt for wild celebrations, with Chelsea's players mobbing Ancelotti on the touchline. It sparked memories of when they did the same thing to the former manager Luiz Felipe Scolari after Frank Lampard's 90th-minute winner against Stoke City on 17 January 2009. Scolari was sacked three weeks later.

Ancelotti is slightly more secure in his employment, with the Chelsea owner, Roman Abramovich, prepared to demonstrate his faith in him by giving him money to spend in this month's transfer window. Ancelotti admitted once again that "we need some players", with central defence being one area for improvement. He has an interest in Benfica's David Luiz.

The Italian was critical of his players' loss of concentration at the death but he denied that it was down to their over-celebrating Terry's goal. "It wasn't because of that," said the manager, whose team have not won successive league games since October. "It was a mistake. We conceded easy crosses and we didn't mark in the box. When we thought the game was won, we lost two points in the last situation and so for this reason, I am disappointed. When you deserve to win, you need to win. It is our fault because we were not able to maintain concentration until the end."

Ancelotti admitted that the gap in the table to United was not "light", but he adopted a defiant tone when he insisted that his team was not yet out of the title race. The key to the comeback, he said, was to beat United at home, which he accepted had become a necessity. The match is scheduled for 1 March.

"Firstly, United have to win their game in hand," he said, "and secondly, the gap is not a light gap in this moment but everything is still open. We have to beat them here and that will say something about the title. We need to beat them here. The title race is not over because we are improving and we can say something about it."

A further cause for concern for Ancelotti were the performances of his chief goal threats, Drogba and Nicolas Anelka. Although Drogba scored Chelsea's equaliser at 2-2, he was generally poor while Anelka was anonymous and has not scored since 3 November. "They have difficulty in this moment but Drogba scored today and for a striker, that's very important," Ancelotti said. "I think he is moving on from this difficult moment. In the last game [against Bolton], Florent Malouda scored, now Didier has scored and in the next game, I hope Anelka can score."

Villa had arrived in London on a run of five league defeats in six and with pressure building on the manager Gérard Houllier. "It was a game where we got our reward in the end," Houllier said. "We showed character and bravery," Houllier said. "We didn't bottle out. This can be a turning point."