That Manchester United did well in the Champions League this week is obvious, but so did Arsenal. Their 2-1 defeat in Porto may not have been as spectacular a result as United's 3-2 win in Milan, but Sol Campbell's away goal made it a good result nevertheless.
For years the mantra in Europe was play for a clean sheet away from home, then steamroller the opposition at home knowing that, if required, extra time and penalties would be on familiar territory. Visiting teams would get men behind the ball, soak up pressure, and go home happy with a 1-0 defeat.
Things have changed. In the last two seasons, seeded teams at this stage (the only seeded knockout round) have failed to reach the quarter-finals seven times out of 16. Not much of a return, considering these are the group winners, therefore presumably the stronger teams, and have the supposed advantage of a home second leg. The previous two seasons had run to form with 14 seeds progressing.
The telling development may be the growing focus on quick counter-attacks (as illustrated against Arsenal by Manchester United and Chelsea). Away teams still get men behind the ball, but when they break they do so in numbers, at pace. As Sir Alex Ferguson noted: "The speed of transition play is much quicker today, and most counters involve a group of four or five players flooding forward." Which means relying on being able to throw numbers forward at home is a dangerous tactic.
Instead, the aim should be to score away. In the last four seasons 11 teams failed to score in an away first leg, only four progressed and all achieved goalless draws. Of the 21 teams who secured an away goal all but two progressed. Second-leg home advantage is minimal if a team fails to score in the first leg.
So, the message for Chelsea against Inter, in Milan next week is, like Manchester United and Arsenal: score.