The 2-1 defeat at Tottenham cut Chelsea's lead at the top of the Premier League to one point and they have now lost their captain into the bargain.
Terry was sent off after being booked twice within three second-half minutes for ill-judged challenges and he will miss their next game against Stoke. The defender also gave away a penalty for hand-ball and is enduring a miserable end to the season.
Marching orders: John Terry picked up two yellow cards in three minutes
Accused of making a tackle so dangerous it could have ended the career of England team-mate James Milner against Aston Villa in the FA Cup semi-final last week, he was also lucky to escape a hand-ball appeal against Bolton three days later.
Tottenham manager Harry Redknapp claimed Saturday's penalty decision was 'harsh' but that was little consolation for Terry.
Ancelotti said: 'Terry is under pressure but everyone is. He is the captain and is involved in this exciting title race, but there is nothing special on him. John tried to do his best but it was not a good day for us.'
What's the point: Carlo Ancelotti barks some orders
Paul Scholes' late winner for Manchester United at Manchester City earlier in the day had put pressure on Chelsea to maintain their advantage. Their failure to do so means they have three games left to maintain their slender lead.
After Stoke, they go to Liverpool and face Wigan in the final game of the season.
Ancelotti said: 'I am always confident. I am less confident than yesterday but we are in the best position.
'We played soft and it was impossible to recover after missing Terry. Having one point more isn't bad and the other teams would want to be in our position.
'We have to be better than in this game and need to win all three games to be sure, but we don't need to panic.'
Ancelotti was adamant Scholes' goal in added time at City had not damaged Chelsea mentally before they faced Spurs. But it certainly gave Tottenham a fillip.
Skipper Michael Dawson admitted: 'The lads were having their lunch and when Scholes scored there was a little cheer. Fourth spot is back in our hands.'
Spurs can now look forward to an exciting end to the season with a two-point advantage over their nearest rivals, Manchester City, in the race for the last Champions League place.
'The championship is wide open again,' said Redknapp after his side made it seven wins out of eight in the league.
'We had to raise our game after beating Arsenal and we did that. We should have won it easier because we had three or four unbelievable chances to really kill them off.'
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