The Champions League returns this week with plenty of intriguing storylines, from Manchester United 's reunion with a famous European opponent to Aston Villa 's latest test against one of the continent's elite.
Paris Saint-Germain are looking to continue their remarkable dominance of the competition, while Liverpool head to Istanbul for a reunion with a familiar face. Elsewhere, a former Real Madrid flop will be hoping to make his old employers regret letting him go.
Here are five talking points ahead of this week's Champions League action.
Michael Carrick 's status as Manchester United manager appears to be on life support right now, with a nine-game winless run in all competitions seeing some suggest the axe is being sharpened.
Off-field tensions and a string of disappointing performances have intensified scrutiny, ahead of Tuesday's Champions League meeting with AS Roma at Old Trafford.
The clash with Roma will evoke memories of one of Carrick's finest nights. The midfielder scored twice as Manchester United thrashed the Serie A side 7-1 in the 2006/07 quarter-finals, as Sir Alex Ferguson's side bounced back from poor recent results to deliver one of the most memorable European nights in club history. How Carrick could do with a repeat.
Aston Villa's farcical fallout with Jamie Carragher this week was an unneeded distraction to what has been a quietly impressive start to the season. Despite mass exits in the summer, Villa are unbeaten in their last five Premier League games, and have maximum points in the Champions League.
Villa are determined to establish themselves among the elite of English and European football, and their performances in the Champions League offer plenty of encouragement.
Unai Emery's side became the second quickest team in European Cup/Champions League history to record 20 wins in the competition last time out, achieving the feat in only their 30th fixture. Only Real Madrid (29 games) have reached that milestone quicker.
Villa face a huge test of their progress this week, with a trip to face Barcelona at Camp Nou.
Having conquered Europe in each of the previous two seasons, Paris Saint-Germain have started the new campaign in ominous fashion.
Luis Enrique's men lead the league phase table with a perfect record after three games, ahead of this week's meeting with Villarreal. PSG have achieved maximum points in style.
The back-to-back Champions League winners have set a new record for goals scored after three Champions League group games (14), despite facing sides considered contenders in Manchester City and Barcelona. The French side are formidable.
Liverpool also have a perfect record after three games ahead of a visit to Istanbul this week. The Reds takes on Fenerbahce at The Şükrü Saracoğlu Stadium, with the usual ferocious atmosphere expected.
The fixture takes on an intriguing sub-plot, after the appointment of ex-Liverpool favourite Dirk Kuyt as interim manager of the Turkish side. Kuyt scored 71 goals in 285 games across six seasons at Anfield, including a consolation in the 2007 Champions League final.
Now tasked with reviving Fenerbahce's faltering season, Kuyt has an immediate opportunity to make an impression against his former club.
Luka Jovic's Real Madrid career never came close to matching expectations. Signed for €60m after an outstanding spell at Eintracht Frankfurt, the Serbian striker managed just three goals in 51 appearances for the Spanish giants.
After a poor period post-Madrid, Jovic has found a home at AEK Athens. The 28-year-old has scored 28 goals in 58 games for the club and fired AEK to Greek Super League success last season.
He comes face-to-face with his old side in the Greek capital this week, and will want to prove a point.
