Each with two Champions League triumphs on their managerial CVs, two of them are attempting to work their European magic in new surroundings while the third has returned to the club at which the continent's biggest club prize proved elusive. (Agencies)
After a year-long sabbatical, having twice taken Barcelona to European glory in a glittering reign, Guardiola has arrived at Bayern Munich tasked with retaining the trophy won in such style by Jupp Heynckes in May.
Ancelotti, after his brief stay at Paris St Germain, will be expected to deliver Real Madrid's 10th European Cup without delay, having twice led Milan to the summit.
Mourinho, who Ancelotti has replaced in the Spanish capital, will seek to steer Chelsea all the way to the final in Lisbon having returned to London determined to win club football's biggest prize with a third club.
Guardiola's Bayern open the defence of their crown at home to CSKA Moscow, Real Madrid will unleash Cristiano Ronaldo and Gareth Bale in Turkey against Galatasaray while Chelsea face Swiss side FC Basel at Stamford Bridge.
Rafa Benitez, another manager with a proven Champions League pedigree, will have to hit the ground running as his Napoli side host last season's runners-up Borussia Dortmund in what looks like being a devilishly difficult Group F.
With so many Champions League masterminds among the 32 coaches setting off this week, Manchester United's David Moyes and Barcelona's new coach Gerardo Martino look like rookies in comparison as they prepare for their first ventures in the groups stages of the tournament.
Moyes will need all his steely calm and self belief as he plots United's first Champions League campaign in the post-Alex Fergsuon era.
The Scot will have a tough baptism with Bundesliga side Bayer Leverkusen first up on Tuesday in a group that also contains Real Sociedad and Ukraine champions Shakhtar Donetsk.
A good start in Europe will go a long way to helping Moyes establish himself but the Champions League, as even Fergsuon would testify to, can be an unforgiving place.
"(Ferguson) said he thinks this is one of the hardest draws United have had in the Champions League," Moyes, whose only flirtation with the competition was a final qualifying round defeat while in charge at Everton, said.
Martino has started life confidently at the Nou Camp and with Lionel Messi already having scored six league goals and with Brazilian Neymar about to make his Champions League bow, Barca will again start as one of the favourites.
The Catalans are in Group H - the only section comprised of all former winners - with Celtic, Milan and Ajax Amsterdam who they begin against on Wednesday in one of the ties of the week.
While Moyes may be a novice at this level, albeit with a team containing the likes of Robin van Persie and Wayne Rooney, rivals Manchester City have recruited a vastly-experienced European coach in Manuel Pellegrini.
City's away tie against Group D minnows Viktoria Plzen on Tuesday will be the Chilean's 45th in the Champions League and the club's owners will be expecting a vast improvement on the previous two seasons in which they have managed only three wins in 12 group games.
Bayern are also in City's group, but Pellegrini, who steered Malaga to the quarter-finals last season, has warned against taking Czech side Plzen or CSKA Moscow lightly.
"If we think we are going to qualify for the last 16 because the other teams are weak we will be making a mistake," he said.
Mourinho, who announced himself as a coaching heavyweight by taking Porto all the way and repeated the feat with Inter Milan, will be taking charge of his 108th Champions League game when Chelsea host Basel on Tuesday.
The Portuguese's last Champions League game in charge of Chelsea was a 1-1 draw against Rosenborg in 2007 - a result that signalled the end of his first spell in charge of the club.
Chelsea bowed out of the Champions League at the group stage last season when they were the holders, but with Mourinho back at the helm and a kind group which also includes Steaua Bucharest and Schalke a strong run is expected.
Ancelotti, who like Mourinho suffered Champions League disappointment while at Chelsea, has a mouthwatering array of talent at his disposal but finding the best system to incorporate the likes of Ronaldo, Bale, Luka Modric and Isco will be key to his chances of succeeding where others failed.
An away match at Galatasaray will offer some early clues. The Italian clubs are not being touted as potential champions this year but Napoli, Juventus and Milan will all bring plenty to the party in the coming months.
Paris St Germain, one of only two French clubs in the group phase, begin away to Olympiakos on Tuesday while Marseille host English regulars Arsenal on Wednesday.
Each with two Champions League triumphs on their managerial CVs, two of them are attempting to work their European magic in new surroundings while the third has returned to the club at which the continent's biggest club prize proved elusive.