Jose Mourinho admits Chelsea are having to score more goals to compensate for the defensive frailties that are threatening to undermine their Premiership title defence.

The Blues dropped two crucial points when Michael Essien deflected an Ashley Cole clearance into his own net with five minutes remaining of yesterday's 2-2 draw with Reading at Stamford Bridge.

It was a remarkable ending to the match with Didier Drogba having put Chelsea ahead in each half, either side of an equaliser from Leroy Lita.

To compound matters, Mourinho revealed captain John Terry might require surgery on the recurring back problem that has forced him to miss the last four matches.

Ricardo Carvalho was paired alongside right-back Paulo Ferreira in the centre of defence and Mourinho admits Chelsea are struggling without Terry and first-choice keeper Petr Cech.

He said: "To lose Petr and John at the same time is a very difficult problem to solve, especially in a squad without more central defenders.

"We sold William Gallas and Robert Huth in the summer. We don't have enough cover so at this moment in time we are having problems.

"Normally for Chelsea three consecutive matches would mean three clean sheets but at this moment in three consecutive matches we have conceded six goals.

"So for us to win matches right now we need to score three times. Sometimes we'll do it, sometimes we won't."

Reading controlled spells of the second half with Kevin Doyle and Brynjar Gunnarsson missing chances to equalise before Essien did the job for them.

Lita's 67th-minute finish, which concluded a jinking run and fine pass from Glen Little, was no more than the Royals deserved and boss Steve Coppell felt his side could have snatched all three points.

He said: "It was interesting the way the game developed. I thought it was stagnant for long periods of the first half.

"We had a defined gameplan and the players stuck resolutely to that. I think 1-0 down is a precarious position to be in but we really pushed on.

"There was a real determination in the dressing room. The players were very positive and the momentum was with us for the second half.

"Once we got back in I thought we might have gone on to win the game. We had a bit of fortune for the second goal.

"We are pleased with the point because we haven't being played well recently."