But just why the supersonic Brazilian seems to love Chelsea so much only he really knows. The north London club thought it had stolen a march on its rival a medical had been completed before the transfer from Russian club Anzhi Makhachkala was hijacked by Chelsea's Russian owner, Roman Abramovich.
Hazard played well in his side's 1-1 draw against Barcelona in the Champions League knockout round first leg but his performance might have summed up his time in west London. The most obvious was self-handicapping.
His pace, energy and quick feet made him the people's choice for man of the match as he upstaged Eden Hazard and Lionel Messi. He ended up with a nearly perfect game at Stamford Bridge. On the wing I feel more comfortable.
Chelsea play-maker Eden Hazard has played down comparisons with Barcelona's Lionel Messi and Real Madrid's Cristiano Ronaldo, saying he is a completely different player. On the one hand, glory and praise.
And when your boss is a workaholic, it is hard graft that catches his eye, not flamboyant football and dizzying feet.
To be fair to Christensen, he has been a revelation since coming into the Blues starting XI earlier this season. A 1-0 victory was the best realistic scenario for the game plan he chose. He's spent £58m on a Champions League substitute, an uncomfortable situation that may not be entirely of his making. The closest we can get to the answer to this question is by looking at bookmakers' odds for this match-up. Despite many doubts among Chelsea fans and pundits, Antonio Conte showed once more that he's a tactician par excellence. Every time I came in, I always tried to do my best.
There have been doubts, though. We are talking about a player who is only 21 years old. No spontaneous outpourings of elation, no playful ruffling of hair, no gurning for the cameras. I am very happy.
Lewandowski's recurring heebie-jeebies in front of the Gladbach net, however, has cost his teams points - indeed, his last eight appearances (two with Dortmund, six with Bayern) have brought two wins, two draws and four defeats.
"We must be realistic".
The diminutive Argentine atoned on Tuesday, giving Barcelona a precious away goal as he strode on to a pass from Andres Iniesta in the 75th minute and calmly side-footed the ball home to cancel out Willian's opener for Chelsea 13 minutes earlier.
Christensen signed for Chelsea in 2012 and has won 14 caps for Denmark.
"It's not over. We can still dream". Planning to play out of possession and strike on the counter-attack, he needed players who could break out quickly. While not a big, voluble dressing room presence, he leads by example.
On Sunday, Manchester United host Chelsea in the English Premier League.