The big-spending Blues were in the process of changing the face of English football forever under Roman Abramovich, while Premier League teams in general were once again beginning to make their mark on a consistent basis in Europe.
A year after Liverpool pulled off the 'Miracle of Istanbul', Arsenal became the second English side in succession to reach the final of the Champions League in 2006, ultimately falling short at the hands of Barcelona.
Liverpool themselves did pick up another piece of silverware under Rafael Benitez, though, with the Steven Gerrard-inspired Merseysiders winning one of the best FA Cup finals in recent memory at West Ham United's expense.
Gerrard pipped Premier League top scorer Thierry Henry to the PFA Player of the Year award, but Henry was named FWA Footballer of the Year and Premier League Player of the Season, while Wayne Rooney scooped the PFA Young Player of the Year gong.
Here, with the 2019-20 campaign stranded after gameweek 29 due to the coronavirus pandemic, Sports Mole takes a look at what would have happened if the 2005-06 season ended at the same stage.
Chelsea were once again crowned champions as Mourinho made it back-to-back Premier League titles, although they may have preferred the season to have lasted only 29 games.
The Blues were 15 points clear at this stage of the 2005-06 campaign and looked certain to cruise to the title, only for a sudden dip in form to see that gap close to only seven at one stage, with Manchester United stringing together a run of nine wins in a row to ramp up the pressure.
However, Mourinho's side soon steadied the ship and ended up eight points clear of Sir Alex Ferguson's United, memorably beating the Red Devils at Stamford Bridge to secure the title.
Liverpool won their final nine games of the season to finish just one point behind United and a whopping 15 points clear of fourth-placed Arsenal, who pipped North London rivals Tottenham Hotspur to the final Champions League spot by just two points in their final season at Highbury.
That would have been different after gameweek 29, when Spurs were instead two points clear of eventual Champions League runners-up Arsenal; it would take Tottenham another four seasons before they finally made it back into Europe's top-tier competition.
At the other end of the table West Bromwich Albion, who had pulled off the 'Great Escape' the previous season, were on the wrong end of one this time as Portsmouth won five and lost just two of their final nine games.
Pompey had been 19th and six points from safety after 29 games, but their end-of-season surge saw them finish four points clear of the relegation zone.
Birmingham City went down despite picking up 10 points from their last 10 games, while West Brom managed only three points from the final 27 on offer to join them and Sunderland, who won only 15 points all season, in the Championship for 2006-07.
Newcastle United were the biggest climbers during the final months of the campaign, moving from 12th to seventh courtesy of a 19-point haul from their last nine games, while Fulham took 16 points from their last eight outings to rise from 16th to 12th.
Manchester City suffered the biggest drop, meanwhile, losing eight of their final nine outings to plummet from 10th to 15th.
Elsewhere, Blackburn Rovers would have held on to the UEFA Cup spot in sixth, while Premier League debutants Wigan Athletic upset the odds by finishing in the top half despite a two-place fall between gameweek 29 and gameweek 38.