Manchester City failed to score at home for the first time since November 2010 as Chelsea beat them 1-0 to draw level in the English Premier League title race.
Branislav Ivanovic's first-half goal proved enough to condemn City to their first home defeat of the season - having scored 42 goals at Eastlands before Monday night's match.
The three points move Chelsea level on 53 with City, two points behind leaders Arsenal.
Chelsea captain John Terry said manager Jose Mourinho had won the battle against opposite number Manuel Pellegrini both on the training pitch and in Manchester.
"We showed a lot of character, and created a lot of chances. We spent a good couple of days working on their strengths and weaknesses," he told Sky Sports.
"That is typical Jose Mourinho."
Pellegrini went into the match without injured top-scorer Sergio Aguero, but still had a source of goals in abundance through Alvaro Negredo and Edin Dzeko.
But the only goal of the game was to come from the unlikely boot of Chelsea's Serbian defender Ivanovic, who fired into the bottom corner after Vincent Kompany had blocked Ramires' shot after 32 minutes.
Mourinho suggested afterwards that the win still might not have a big impact on the title race, saying that the "evolution" of the team since he began his second spell in charge in the summer was more important.
"We can (win the title) if they lose it," the Portuguese told the BBC, before deadpanning the victory in a manner that could be interpreted as tongue-in-cheek.
"It means nothing for us to come here and park the bus and win 1-0 in a lucky situation."
In the game between the team with the best attack and the one with the meanest defence in the league, both managers chose a more defensive midfield than usual.
Centre backs Martin Demichelis of City and David Luiz of Chelsea were played in the centre of midfield, and the visitors' playmaker Oscar was left on the bench.
City threatened when Alvaro Negredo, who had scored 16 times in his last 13 competitive games at home, fired over and Yaya Toure twice went close, but David Silva had the best opportunity after 18 minutes when his close range attempt went wide.
But after Ivanovic put them in front, Chelsea had the best chances of the game, hitting the woodwork three times while still parking that bus sufficiently to frustrate a team that, in Mourinho's words, had "smashed" every other visitor at home this season.