Essien, who cost the Blues £24.4 million, ran the game from start to finish for the Barclays Premiership champions, who now top Group G thanks to their rout of the Spaniards at Stamford Bridge.
Goals from Didier Drogba and Ricardo Carvalho gave Chelsea a priceless advantage at the interval and they completed the demolition job with further strikes from Joe Cole and substitute Hernan Crespo.
Cole dedicated his strike to his father George who is in hospital after suffering a minor heart attack a few days before the game.
Underpinning Chelsea’s victory though was the tireless work of the Ghana international Essien, who was instrumental in the build-up to their first and third goals. “He was the best player on the pitch,” enthused a delighted Mourinho. “He won every challenge in midfield and gave a different pace to the game.
“He was too strong for Betis and recovered a high percentage of balls. He was crucial in the build-up to the first and third goals. He was too powerful for them.
“I think it was his best game - a more complete one than he has played. Overall I think his performance was amazing.”
Mourinho’s side are now just one win away from qualification for the next phase of the competition and have yet to concede a goal in Europe this season.
To a man, Chelsea were significantly better than Betis, but Mourinho was still unhappy with the way his side failed to cope with Spaniards in the air during the early stages.
“If they had scored first we would have seen a totally different game,” he conceded.
“We played against Liverpool and against Bolton with players 1.85, 1.90, 1.95 and Peter Crouch 2.0 metres, and we had no problems with set-pieces. Against Betis with only one player over 1.85 metres, it is unacceptable the problems we had from set-pieces in the first 15 minutes. “The result was a consequence of 2-0 in front at half-time.
“In the second half they tried but they gave us a lot of space and we scored two more goals. We could have scored four or five more.
“They started well and maybe better than us but in football the first goal is always important because it gives more confidence. They played good football and were always dangerous until we scored the third goal - it killed the game. I know in 15 days’ time we will have a difficult game in Betis.”
But the Portuguese coach refused to get carried away with a result that will undoubtedly send a warning to the rest of Europe whether Mourinho likes it or not.
Chelsea are nine points clear at the top of the Premiership with nine straight wins and have hit 13 goals in the last three games.
“We don’t want to send messages,” he said. “We just want to achieve our targets and they are to win the Premier League and, for a start, be in the next stage of the Champions League. At this moment we have seven points and it is a good situation for us.”
Chelsea skipper John Terry was also full of praise for Essien.
“He’s been a different class since he’s been here,” Terry said. “It was going to be difficult but he’s fitted in with everyone and has been outstanding on the pitch.”
Betis coach Lorenzo Serra Ferrer insists they had much to learn from the lesson Chelsea handed out to them and conceded the Blues’ second goal just seconds before the interval was the killer blow.
“We were playing against a great side,” admitted Ferrer. “We had a good lesson out there. Chelsea competed better, fought harder for the 50-50 balls all over the field.
“The second goal on the stroke of half-time really affected us. We went into the dressing room a little bit down.
“I think we can take stuff from this defeat. It is all about learning - both for me and the players.
“We will take a look at things calmly in order to learn and improve for the next game.”
: Cudicini, Ricardo Carvalho, Terry, Gallas, Del Horno, Makelele (Diarra 76), Wright-Phillips (Gudjohnsen 66), Lampard, Essien, Joe Cole, Drogba (Crespo 45).
: Doblas, Melli, Juanito, Rivas, Oscar Lopez (Xisco 45), Varela, Miguel Angel (Assuncao 56), Rivera, Edu, Oliveira, Joaquin.
: Terje Hauge (Norway).