Madrid: Factfile on Atletico Madrid and Chelsea ahead of their Champions League semi-final, first leg tie at the Vicente Calderon on Tuesday:
Form: Atletico need to win just three of their remaining four La Liga games to win the title for the first time since coach Diego Simeone played for the club 18 years ago.
Friday's hard-fought 2-0 win over Elche stretched their winning run to eight games in domestic competition and they have been similarly strong in Europe this season.
Atletico are undefeated in 10 Champions League games so far this campaign and have won all five at home.
In contrast, Chelsea's title hopes look all but over after they lost a league game at home under Jose Mourinho for the first time in 78 matches as they were stunned 2-1 by bottom-placed Sunderland on Saturday.
The 2012 European champions have now lost four times in their last nine games in all competitions, but did manage a fine 2-0 win over Paris Saint-Germain in that run to book their place in the semi-finals for the seventh time in 10 years.
Atletico Madrid: Diego Simeone (ARG)- 43
Chelsea: Jose Mourinho (POR) - 51
Leading scorers in all competitions
Atletico Madrid: Diego Costa (35 goals)
Chelsea: Eden Hazard (17 goals)
Atletico Madrid Diego Costa and Chelsea Eden Hazard
Domestic league performance
Atletico Madrid: First in La Liga with four games to go, six points ahead of Real Madrid but having played one game more.
Chelsea: Second in the Premier League, five points behind leaders Liverpool with three games left
Route to the semi-finals:
Atletico Madrid: Winners of Group G ahead of Zenit St. Petersburg; beat AC Milan 5-1 on aggregate in last 16; beat Barcelona 2-1 on aggregate in quarter-finals.
Chelsea: Winners of Group E ahead of Schalke; beat Galatasaray 3-1 on aggregate in last 16; progressed on away goals against Paris Saint-Germain after scores tied at 3-3 in quarter-finals.
European Cup/Champions League best performances:
Atletico Madrid: runners-up 1974
Chelsea: winners (2012)
Atletico Madrid: 9 x Spanish champions, 10 x Copa del Rey winners, 2 x Europa League winners, 1 x Cup Winners' Cup winners, 1 x Intercontinental Cup winners
Chelsea: 4 x English champions, 7 x FA Cup winners, 4 x League Cup winners, 1 x Europa League winners, 2 x Cup Winners' Cup winners, 1 x European Super Cup winners
The sides have met three times in all in European competition with the spoils shared at a win for either sides and a draw.
Atletico won the European Supercup in 2012 as a first-half Radamel Falcao hat-trick powered them to a 4-1 win in Monaco.
Chelsea had the upper hand when the sides met in the Group Stages in 2009, though, as after a 4-0 win for the hosts at Stamford Bridge, the English side sealed their passage into the last 16 with a 2-2 draw in Madrid.