A new era, but familiar problems remain. Chelsea dominated, failed to pull clear, conceded, drew. Obviously, it could have been worse. Yet Graham Potter, attending his first Champions League game whether as participant or spectator, would have hoped for more.There were 15 minutes remaining when Salzburg, who had been second best much of the game, caused Stamford Bridge to fall silent for the second time in the night. An impressive exchange of passes, from the back and through the midfield, ended with substitute Junior Adamu sprinting down the right flank. His low cross was met by Swiss international Noah Okafar, who lost Thiago Silva, and turned the ball smartly past goalkeeper Kepa Arrizabalaga. First time, too, Potter will have noticed. How Chelsea could have done with a similar sense of determination when the target loomed.It wasn’t like they weren’t warned, either. And not only by the many matches that have unfolded like this dating back several years. Even on the night, the signs were there. Just two minutes earlier, Okafor had forced a fine save from Arrizabalaga with a flicked header, at a time in the game when many had decided one would be enough for Chelsea. One isn’t enough, these days. Earlier this week, Potter admitted he had never attended a match in this competition, let alone been involved in one, and now he knows how hard it is, even against those teams the Super League snobs would class as fodder.