And so it goes on. Shakhtar Donetsk beat Metalurh Zaporizhzhya 2-0 on Saturday – Douglas Costa converted a penalty before a late goal from Luiz Adriano sealed it – to take their winning streak in the Ukrainian league to 23 games, 14 of them this season. They lead the table by 12 points and, already, with the season one game from its halfway point, it seems inconceivable that they will not lift a seventh title in nine years. The focus, understandably, is all on the Champions League and Wednesday's game against Chelsea.

At the moment, Shakhtar are in a happy position. They can rest players domestically, essentially using those games as practice matches, clocking up the wins, building confidence, perhaps experimenting with tactical tweaks. Although the party line is to spout the usual platitudes about no easy games, the Armenian Henrikh Mkhitaryan let the truth slip when asked if he'd had to work "really hard" in the home game against Chelsea a fortnight ago. "Yes," he replied. "This is not the Ukrainian championship. When playing in the Champions League, you must move faster, close down the zones, orchestrate fast attacks. There are no weak opponents. All the teams are very strong. We must know how to defend, how to attack."

The long-term prognosis, though, may be less positive. It's not easy for teams used to winning comfortably at home to then raise their level for the tougher battles of the Champions League. If an average game is won 3-0 or 4-0, they lose defensive focus, forget how to fight. Given their form – in all competitions the only game Shakhtar have not won this season was the 1-1 draw at Juventus – it seems absurd to criticise, but they have conceded soft goals against both Juve and Chelsea.

In fact – and again, this feels like ludicrous nitpicking – their Champions League record this season should be even better than it is. Shakhtar have controlled all three matches, have created tons of chances, and yet their goal difference is only 5-2. They have been wasteful in front of goal in all three games – albeit against Chelsea in part because of a superb performance from Petr Cech. Now perhaps that is coincidence – all teams have games in which they miss chances – but it may also be that Shakhtar lack a certain edge in front of goal.

Some would blame Luiz Adriano, and it is true that his strength as a centre-forward is bringing others into play and creating space rather than finishing, but he is not the only one who's been profligate; it may be that when a team are used to creating a couple of dozen chances a game, a certain sloppiness can creep in. Shakhtar could really do with Dynamo Kyiv getting their act together soon.

That, though, is the one small negative in what has otherwise been an utterly exceptional season for Shakhtar. The difference to last season, when they finished bottom of their Champions League group after a series of limp displays, could hardly be greater. "Last year, if you remember, there were problems in the first game when the referee sent off two of our players," Mircea Lucescu, the manager, explained. "Fernandinho wasn't fit. There were also other problems regarding the fitness of our players.

"Last year's exit from the group stage made us regroup, analysing once again everything we had been doing. By winning the championship, cup and Super Cup, we tried to make up for our exit from the Champions League. We won all these titles, and it gave us confidence. The level of this year's competition for first-team places has resulted in our players' improvement."

Fernandinho's return from injury has been a major positive, partly because it allows Mkhitaryan to play further forward – in the position Jadson used to occupy – but also because he is the ideal player to link back and front of the team. Tomas Hubchsman sits deep to protect the back four and Fernandinho distributes while being willing to carry the ball forward and make the sort of runs that led to the second goal a fortnight ago.

It was in the wide areas, though, that Shakhtar really hurt Chelsea. Roberto Di Matteo has spoken repeatedly this season of the need for "balance", of giving his creators freedom without losing defensive stability. In Donetsk, he left out Eden Hazard, playing Juan Mata on the left with Ramires on the right and Oscar central, but again his full-backs were left exposed.

Ramires effectively cancelled out Razvan Rat in the first half – as he had Kwadwo Asamoah in the Juventus game – but on the left Mata may as well not have been there for all the attention Darijo Srna paid him. Mata is reasonably diligent about his defensive duties – see the way he robbed Kyle Walker before laying on Chelsea's fourth at Tottenham – but he simply couldn't cope with Srna's energy as he bounded past him again and again. There seemed to be an attempt by Chelsea to meet fire with fire on that flank, particularly after half-time when Hazard came on, and Ashley Cole was far more attacking than Branislav Ivanovic. All that meant, though, was Alex Teixeira finding space or being able to isolate Cole.

The other key to Shakhtar's domination in the first game was Mkhitaryan, who seemed to find it far easier to escape Mikel John Obi than Oscar did to get away from Hubschman at the other end. That perhaps lay behind the decision to substitute Frank Lampard and move Ramires into a holding role when Hazard was introduced. The Brazilian did, to an extent, check the surges of Fernandinho, but Mkhitaryan, one of those players with an enviable comprehension of where other players are, seemed always to find space.

Chelsea's approach to Wednesday's game will be fascinating. Do they assume that with home advantage they will be able to impose themselves, knowing that if they can keep the ball in the final third Shakhtar are vulnerable? Or do they take measures to negate Shakhtar?

It seems bizarre to discuss breaking up the Hazard-Oscar-Mata front three, or at least bringing in any one else but Ramires, but perhaps Ryan Bertrand could be deployed on the left to try to check Srna (or Ramires could play on that flank, as he did in the first leg against Barcelona). Will Mikel be able to cope with Mkhitaryan? And how will Ivanovic deal with Willian – by sitting deep or by attempting to bypass him by simply playing higher up the pitch?

This is a vital game – for Chelsea particularly – but it is also a fascinating game tactically between two sides who essentially look to play the same way.