John Terry came to Chelsea's rescue on Wednesday when he powered home a 77th-minute header to secure a 1-0 home win over a dogged AS Roma.
AS Roma and Manchester City clash for a place in the last 16 of the Champions League.
Serie A leaders Inter Milan beat AC Milan 2-1 to extend their advantage over AS Roma to seven points.
A second-half Mancini goal earned AS Roma a 1-1 draw with Manchester United in the Champions League on Wednesday.
Inter Milan stayed three points clear at the top of Serie A after a 3-0 home win over Lazio.
Manchester City conceded four goals in 36 hapless minutes on Saturday as they slumped to a 4-2 defeat by VfB Stuttgart in a pre-season friendly.
AC Milan striker Marco Borriello has been suspended after testing positive in a routine doping test.
A second-half header from Mirko Vucinic gave AS Roma a 1-0 win at struggling AC Milan that lifted them into second spot in Serie A.
The draw interrupted a run of four straight league wins for Zinedine Zidane's side and left them second on 67 points after 31 games, three behind leaders Atletico who thrashed Eibar 5-0 earlier in the day.
Manchester United beat AS Roma 1-0 in the second leg of their Group F Champions League meet.
Manchester United manager Alex Ferguson is expecting AS Roma to come looking for revenge in their Champions League tie on Tuesday.
Paris St Germain will play Borussia Dortmund and Barcelona were pitted against an unpredictable Napoli, while Chelsea were drawn against Bayern Munich. City, who will be at home in the second leg, have yet to beat the Spanish side with two draws and two defeats in their previous four meetings.
Two supporters were kept in overnight and a local hospital spokesman said one fan had suffered stomach wounds as 10-man United lost their quarter-final, first leg 2-1.
Manchester United and Chelsea will both be putting their quests for domestic dominance to one side on Wednesday and turning their attentions instead to European glory.
Chelsea also got their Champions League campaign off to a good start, beating Werder Bremen 2-0.
Liverpool signed Brazil international Alisson from AS Roma on Thursday, smashing the world record for a goalkeeper in a deal worth up to 72.5 million euros ($84 million).
Barcelona rubber-stamped a decade of domestic dominance by clinching the La Liga title on Sunday
Marco Asensio's strike earned Real Madrid a 1-0 win over Espanyol to send them top of La Liga and Thomas Lemar scored his first goal for Atletico Madrid in a 2-0 victory at Getafe on Saturday.
Goals by Marco Materazzi and Zlatan Ibrahimovic gave Serie A leaders Inter Milan a 2-0 victory over Messina on Sunday as they set a club record with their ninth straight league win.
AS Roma won the Italian Cup on a 7-4 aggregate victory despite a 2-1 defeat in the second leg final at holders Inter Milan.
Lionel Messi dragged a nervous Barcelona to a 1-0 win at home to Levante in La Liga, while Cristiano Ronaldo converted two late penalties on his 100th appearance for Juventus in all competitions as the Serie A titleholders ground out a 3-1 win away to a dogged Genoa side.
AS Roma scored four goals in the first half hour to beat holders Inter Milan 6-2 in an extraordinary first leg of the Italian Cup final on Wednesday.
News of all that transpired on and off the football field.
Barcelona coach Ernesto Valverde's conservatism was cited by the Spanish media as the main reason for their 3-0 defeat at AS Roma on Tuesday that led to a shock Champions League quarter-final elimination being regarded as 'a historic debacle'.
The Premier League leaders will be without Rio Ferdinand, Gary Neville, Nemanja Vidic and Mikael Silvestre for their Champions League semi-final against Inter Milan.
Inter Milan beat Siena 2-1 to clinch their second successive Serie A title with five games to spare.
Having lost the first leg 1-2, Manchester United host AS Roma in the Champions League quarterfinals.
News of all that's transpired on and off the football field
Manchester United coach Alex Ferguson remained confident his side would reach the last four of the Champions League despite losing 2-1 to AS Roma in the first leg of their quarter-final on Wednesday.
Zlatan Ibrahimovic scored a dubious penalty as 10-man Inter Milan beat second-from-bottom Empoli 1-0 on Sunday to pull eight points clear at the top of Serie A.
AS Roma captain Francesco Totti has warned Manchester United coach Alex Ferguson not to underestimate him when their two sides play the first leg of their Champions League quarter-final next week.
Barcelona went out of the Champions League in the first knockout phase on the away goals rule despite a 1-0 win over Liverpool.
Inter Milan notched up their 17th successive Serie A victory with a 5-2 win at Catania on Sunday.
Barcelona's fourth defeat of the season left them seventh in the standings on 14 points after 10 games, 12 points behind leaders Atletico.
Zenit St Petersburg and Middlesbrough dented the UEFA Cup hopes of Olympique Marseille and tournament favourites AS Roma.
A round-up of Wednesday's Champions League first knockout round, first leg ties.
Alessandria became the first third tier club to reach the Italian Cup quarter-finals in more than 30 years as their giant-killing run continued with a 2-1 extra-time victory at Serie A strugglers Genoa on Tuesday.
Holders Barcelona will play Premier League leaders Arsenal in the last 16 of the Champions League, 10 years after the sides faced each other in the final, following Monday's draw for the first knockout stage.
Last year's finalists Juventus will face-off against Bundesliga champs Bayern.
Dani Alves appeared to have won the game for Juventus when he headed them in front in the 83rd minute but Remo Freuler pounced to equalise six minutes later as he punished some sloppy defending.