On Wednesday evening, Arsenal defied all expectation by defeating Bayern Munich without reply at the Allianz Arena. No Bundesliga side has done that since Borussia Dortmund in November 2011.
German newspaper Bild said Bayern Munich narrowly avoided a "mega embarrassment" (source in German) at the hands of a brave Arsenal side. The aggregate score was 3-3, yet Die Roten were saved by a rule introduced by UEFA in 1965: The away goals rule.
The rule determines that away goals count double towards the aggregate score in two-legged fixtures such as the Champions League knockout stages. Today, the rationale is to avoid extra time and penalties as tiebreakers, and to encourage the visiting team to be more aggressive.
The rule has proved pivotal in each of the last five Champions League knockout stages. Last season, for example, Marseille eliminated Internazionale for scoring a goal at the San Siro. Inter beat Bayern Munich in the Round of 16 the year before that with a 3-3 aggregate score. In 2009/10, Bayern had their turn of benefiting by Fiorentina with a crucial equalizing strike at the Stadio Artemio Franchi.
On each occasion, the "losing" side has been eliminated without really being defeated thanks to an archaic rule which, in my opinion, should be scrapped.
Hi-res-141378987_crop_exact Valerio Pennicino/Getty Images
The rule was introduced in the 1960s, as an alternative to the utterly arbitrary method of tossing a coin to determine a winner. Back then, getting an away victory in European and international competition was a rare feat. Travel was difficult, conditions were unfamiliar and often belligerent, and home advantage was far greater than it is today.
According to The Guardian's Jonathan Wilson, just 16 percent of European matches resulted in an away victory when the rule was created. Today, that number is between 30 and 35 percent.
Of course, you could argue that the away goals rule has been the catalyst for greater away wins, but it simply cannot be argued that an away trip is as difficult as it used to be.

Homogenized Champions League stadiums provide relatively similar atmospheres for visiting players. Travel is simpler, and most squads are a cosmopolitan blend from all over the world used to foreign conditions.

Does Cristiano Ronaldo really need the crutch of away goals to score at a stadium in Manchester with which he is extremely familiar?
The concept of encouraging away teams by making their goals count double is a double-edged sword: It often discourages home teams. When the opposition have twice the reward at stake each time they find the net, home teams tend to sit back and defend, making for tense games—and less interesting first legs.
In last year's competition, six of the 13 Champions League knockout-stage first-leg ties resulted in 1-0 or 0-0 scorelines. In the second-leg ties, there was an average of 4.4 goals per game.
As Zonal Marking made clear a few seasons ago, there are always more goals in the second leg. Conventional thinking suggests that it is more advantageous to host the second leg, but based on the fact that there are more goals and they are worth double, surely the away team has an unfair advantage in the return match?

The rule also prevents extra time and penalties in the event of an equal aggregate scoreline. Why should we deny teams an extra half-hour of play in which to determine the true winner? Do fans paying extortionate amounts to follow their teams in foreign countries not deserve that?

The penalty shootout is sometimes criticized as being unfair, but it is a far more dramatic tiebreaker than away goals and one that actually requires skill. Furthermore, the drama of a team working to avoid penalties in extra time is some of the best the beautiful game can offer.
Hi-res-109420173_crop_exact Valerio Pennicino/Getty Images
My first experience of the injustice of away goals was the 1997 League Cup semi-final bout between Leicester and Wimbledon. I followed my team, the Dons, up to Filbert Street to watch the first leg. We were probably the better team, but the game finished 0-0. The return leg—to which and The Foxes brought many thousands of raucous fans—was a 1-1 draw, in which we were also probably the better side. At the very least, we were a team that deserved extra time to prove our worth.

Alas, Leicester went through on away goals and Wimbledon remained undefeated in that year's competition. I have struggled to overcome the sheer inequity of the rule ever since.
Even if you argued against all the aforementioned practical sticking points of the away goals rule, it has one insurmountable problem. To paraphrase some some fictional talking pigs, it implies that some goals were created more equal than others.
It's time for FIFA to catch up with the modern intricacies of the game, level the playing field and scrap the away goals rule.