For a brief period during the close season it looked as if Didier Drogba and Sergio Agüero would begin the campaign in tandem at Chelsea, a terrifying prospect that should be enough to send a shiver down the spines of their rivals, even in retrospect.

These contrasting strikers — a raging bull and a nimble matador — illuminated a breathless finale to a bizarre match that left Chelsea assured of their place in the knockout stages, but needing to improve if they are to return to this city for the final in May.

Carlo Ancelotti said afterwards that he would not swap Drogba for any striker in the world, but smiled when asked if he would like to pair him with Agüero. Chelsea are preparing to splash the cash in the January transfer window if Fifa’s transfer ban relating to the signing of Gaël Kakuta from Lens is suspended pending an appeal, although a move for Agüero — despite Ancelotti’s mischief-making — is surely out of the question because of his ineligibility for this competition. “I like him,” Ancelotti said. “I think Agüero can play with Drogba, for sure.”

Agüero’s outrageous wage demands scuppered Chelsea’s plans last summer, although Drogba is close to priceless in his present form. The Ivory Coast striker reclaimed centre stage on his return from suspension by scoring a late double to take his haul for the season to a barely credible 12 from 13 matches, but it is not so much his goals that set him apart from his peers as his all-round contribution.

Drogba’s goals — a far-post header from Florent Malouda’s cross in the 82nd minute followed six minutes later by a superb individual effort in which, after receiving Ashley Cole’s through-ball, he beat Pablo Ibáñez and Juanito, the centre backs, before sending the ball past Sergio Asenjo at the second attempt — appeared to have given Chelsea their fourth straight victory in this competition. However, Agüero was determined not to be overshadowed.

The Argentinian’s contribution after coming on as a 53rd-minute substitute was even more dramatic and his goals slightly better: a stunning volley past Petr Cech to give Atlético Madrid the lead and a beautifully curling free kick to level the match in injury time, although it could not prevent his side’s elimination. The Czech Republic goalkeeper could do nothing about Agüero’s first, but his positioning was poor as he lined up his wall for the free kick.

Agüero’s finishing is as good as anyone’s in the world, although Drogba’s physicality — and superior fitness — arguably set him apart from all his rivals, including Fernando Torres.

The 31-year-old’s workrate is unparalleled for a front man and he offers as much in his own penalty area as at the other end of the pitch, with only John Terry his equal in the crucial area of clearing headers. It says a great deal about Chelsea’s sloppy defending that Drogba’s biggest contributions in the first 60 minutes involved clearing his own lines.

Ancelotti had predicted beforehand that Drogba would be the key to his side’s Champions League hopes, but he will not entirely have enjoyed being proved right so soon. Chelsea were surprisingly poor for much of the match, and rallied only briefly for sporadic spells at the end of each half.

Ancelotti, with half an eye on Sunday’s top-of-the-table clash with Manchester United made six changes from the win away to Bolton Wanderers on Saturday, and initially it showed. The visiting team’s struggles could largely be attributed to being overrun in midfield and the poor quality of their passing, which lacked its usual crispness and clarity of thought.

Michael Essien was particularly culpable, giving away the ball with abandon, to leave Drogba and Salomon Kalou chasing lost causes up front. The Ghana midfield player has many qualities, but will never possess the precision of his illustrious predecessor, Claude Makelele.

Michael Ballack’s strength and stamina were badly missed and he will definitely be back in the starting line-up against United, because it is no coincidence that the Germany captain was also missing during Chelsea’s only defeats this season. The Portuguese pair of Ricardo Carvalho and Deco are also likely to return in place of Alex and Joe Cole, who still has much work to do to regain his best form after nine months out with a knee injury, while Nicolas Anelka’s replacement of Kalou is a certainty.

Ancelotti appeared unconcerned at a disjointed performance, which can be excused given the heights Chelsea have hit in recent weeks, but as well as needing to improve to beat United, such sloppiness will also not be permitted in their next Champions League outing. A defeat in Porto, who have also qualified and have a formidable home record, could cost Chelsea the leadership of group D and condemn them to a more difficult tie in the next round, thus jeopardising their longed for return to Madrid.

Drogba’s return may prove to be timely in more ways than one.

Atlético Madrid (4-1-3-2): S Asenjo — L Perea, P Ibañez, Juanito, A López — P Assunção — J A Reyes (sub: M Rodríguez, 73min), Cléber Santana, Simão (sub: J Jurado, 84) — F Sinama Pongolle (sub: S Agüero, 53), D Forlán. Substitutes not used: D De Gea, R García, T Ujfalusi, A Domínguez. Booked: Reyes, Assunção.

Chelsea (4-1-3-2): P Cech — J Belletti, Alex, J Terry, A Cole — M Essien (sub: M Ballack, 60) — F Lampard, J Cole (sub: Deco, 70), F Malouda — D Drogba, S Kalou (sub: N Anelka, 70). Substitutes not used: Hilário, B Ivanovic, R Carvalho, D Sturridge. Booked: Essien, Terry.

Referee: B Kuipers (Holland)