A decade ago, Diego Milito scored twice as Inter defeated Bayern Munich 2-0 in the Champions League final to achieve what no other Italian team had managed before.

The Nerazzurri's night of triumph at Real Madrid's Santiago Bernabeu saw Jose Mourinho's side complete a Serie A, Coppa Italia and Champions League treble.

It was a crowning moment in the distuinguished coaching career of Mourinho, who signed off in style before becoming a more regular visitor to the Bernabeu.

But was the 2009-10 treble-winning Inter side the best Mourinho team ever?

With the help of Opta, we have assessed Mourinho's best league seasons from spells at Chelsea, Real Madrid and Manchester United to try and answer the question.

CHELSEA 2004-05

Trophies won that season: Premier League, EFL Cup

Performance in Europe: Champions League semi-finals

Mourinho's Chelsea class of 2004-05 were one of the greatest the Premier League has ever seen. The Blues lost just once, racking up a hugely impressive 95 points in the process – a record haul until Pep Guardiola's Manchester City tallied 100 in 2017-18.

The Blues' 72 league goals were shared around the team, with club legend Frank Lampard top scoring with 13. Eidur Gudjohnsen (12) and Didier Drogba (10) also reached double figures.

Lampard, an ever-present in the league, also provided an impressive 18 assists – double the next best effort, which came from Arjen Robben (9). Damien Duff (7), Gudjohnsen (6) and Drogba (5) also weighed in well.

Chelsea were fully functioning going forwards, registering 658 shots in total – 220 of which were on target, an average of 5.8 per game.

But it was at the back where Chelsea were particularly well drilled. They accumulated a sensational 25 clean sheets and conceded just 15 times – the fewest of any team in the competition's history.

Opposition teams managed just 360 shots against Chelsea in total, with only 83 on target – a little over two per game. 

By the end of the campaign, Chelsea earned a league and EFL Cup double, while they exited the Champions League semi-finals to Liverpool and Luis Garcia's famous 'ghost goal'.

INTER 2009-10

Trophies won that season: Serie A, Coppa Italia, Champions League

Performance in Europe: Champions League winners

The greatest achievement of Mourinho's outstanding career?

The Nerazzurri held their nerve in a tense title battle with Roma, who were at the summit after rounds 33 and 34, by just two points.

Inter's win percentage of 63 is lower than the 76 and 84 achieved in the Chelsea and Madrid title-winning campaigns of 04-05 and 11-12, and surprisingly also worse than the 66 per cent of United's 17-18 season.

Indeed, even the 0.89 goals conceded per game is the worst of each of the seasons analysed, although Inter's 34 goals against was the fewest in Serie A that season.

Their 75 goals for – three better than Chelsea managed in 04-05 – was also a league-leading best, and seven better than Roma's, while Inter were only beaten on four occasions.

Milito was the jewel in this Inter crown with 22 Serie A goals, while the former Argentina striker scored the winner in the 1-0 Coppa Italia final win over Roma as well as the brace in the beating of Bayern in the Champions League showpiece. Full-back Maicon was a chief source of provision with 11 assists.

Under Mourinho, who did not lose a home league game as Inter coach, the Nerazzurri kept six Champions League clean sheets in 09-10, while they became the first team to win the competition having failed to win their first three matches.

REAL MADRID 2011-12

Trophies won that season: LaLiga, Supercopa de Espana

Performance in Europe: Champions League semi-finals

Perhaps the most impressive thing about Madrid's record-breaking 2011-12 campaign is that it occurred during the height of Barcelona's breath-taking brilliance under Pep Guardiola.

Los Blancos became the first team in the history of LaLiga to win the title with 100 points, with their Clasico rivals nine adrift.

In a stat completely at odds with Mourinho's reputation for prudence, Madrid's swashbuckling assembly of talent, including Cristiano Ronaldo, Angel Di Maria, Mesut Ozil, Gonzalo Higuain, Kaka and Karim Benzema registered a superb 121 goals – an unbeaten landmark in Spain's top flight.

Ronaldo, unsurprisingly, led the way with 46 LaLiga goals – astonishingly only the second-highest tally in the league that season due to Lionel Messi's scarcely believable 50.

Higuain (22) and Benzema (21) each contributed heavily to the cause, while Jose Callejon, Di Maria and Kaka each chipped in with five.

Madrid had seven players in the top 15 of the assists chart that term. Ozil (17) and Di Maria (15) were creators in chief, while Ronaldo (11), Kaka (10), Higuain (10), Xabi Alonso (9) and Benzema (9) all featured.

In total, Madrid averaged 3.18 goals, 2.47 assists and 7.92 shots on target per game in a campaign in which they were beaten just twice in LaLiga. At the back, they totted up 14 clean sheets and conceded 32 times – the second best defensive record behind Barca (29).

This flamboyant side were knocked out of the Champions League semi-finals by Bayern in a penalty shoot-out, while Barca accounted for their downfall in the Copa del Rey quarters.

MANCHESTER UNITED 2017-18

Trophies won that season: None

Performance in Europe: Champions League last 16

In terms of trophies won, it was Mourinho's debut campaign at Old Trafford that was most successful as United won an EFL Cup and Europa League double in 2016-17.

But their best Premier League performance came in Mourinho's second full campaign, as the Red Devils finished runners-up to rivals Manchester City.

The chasm between City and the chasing pack that season was pretty vast, with United 19 points adrift of the ton-tallying champions.

Scoring goals was a slight issue. United's total of 68 and average of 1.8 per game was only slightly lower in both categories than Mourinho's Chelsea team of 04-05, but was the second-lowest among top-six teams that term.

Mourinho's reputation for pragmatism is backed up by the fact United produced 512 shots and 178 on target (an average of 4.7), areas that are all lower than the Blues' efforts 13 years prior.

At the back, United's backline was breached just 28 times – only one more than City conceded – and they kept clean sheets in exactly half of their league matches. Opposition teams managed 436 shots, 147 of which were on target, against United.

Romelu Lukaku was the chief source of goals, his 16 was seven better than the next best league effort achieved by Anthony Martial (9).

Paul Pogba has often been a much-maligned figure since re-joining United but his 10 assists were the best among Red Devils players that term, with Lukaku laying on seven for his team-mates.

VERDICT

If we are judging this purely on trophies, then Mourinho's Inter of 2009-10 are obviously the winners having achieved something no other Serie A team had managed before.

Chelsea' stoicism of 2004-05 makes them a credible challenger and a contentious decision cost them dearly in that season's Champions League and perhaps a crack at a treble.

But based on entertainment value, and the fact they were up against the best Barcelona team of all-time, the Madrid of 2011-12 is the best Mourinho has ever coached.