The first leg of the Champions League is at an end and the second leg will undoubtedly showcase some tremendous drama.

But before we get ahead of ourselves and the next set of games, it is time to take a look at the four fixtures from this week and glean over the surprises and shocks of the matchups. Here they are:

Porto Destroys Bayern Munich

Of the four games on display, this was arguably the easiest one to call. Or so pundits thought.

Porto made them pay for their predictions by stunning Bayern in the first 10 minutes of the game on their way to a damaging 3-1 win at home. It is true that this is a Bayern Munich side that is struggling with injuries, but the team lost because of calamitous errors from their backline. Xabi Alonso, admittedly a defensive midfielder, was in no-man's land when he was picked up right in front of his box by Ricardo Quaresma. Dante fumbled a routine pass and then lost it to Quaresma who rushed in on Manuel Neuer and calmly slotted home. And then Jerome Boateng mistimed an aerial defense and saw the ball fall to Jackson Martinez, who rounded Neuer and finished the game off.

In the meantime, the offense looked rattled and lacking in vision. And the team is now 90 minutes away from extinction.

On the other hand, Julen Lopetegui played his hand well, having his player pressure Bayern into mistakes incessantly.

PSG Folds in Front of Barcelona and Luis Suarez

Madrid derby withstanding, this was the most hotly anticipated contest. Two big teams that had matched up evenly over the past few years in the battle of their lives.

And yet, Barcelona took control and never let go. Like Munich, Paris Saint-Germain was plagued by injuries entering the game and suffered a huge one when Thiago Silva went down. Barcelona also suffered its own injury to Andres Iniesta, but by then, the tie was ended and Barcelona left the Parc au Princes with a 3-1 victory.

Now PSG needs a 3-0 or 4-1 victory to qualify. Barcelona has conceded three goals in a game twice this year and none of them have come at the Camp Nou. Moreover, the team has never lost by more than two goals this entire season.

Jan Oblak the Star of the Week

The Atletico goalie has rarely featured this year, but he got the surprising call in net in arguably the biggest game of his career. And he came up as huge as they come.

Parrying eight shots away from goal, including a breakaway on Gareth Bale and some tremendous long range blasts, Oblak ensured that his team did not exit the first half down by three goals, which would have been a fair result given the chances and saves he made.

On the flipside, his side rarely looked interested in the game, failing to take advantage of Sergio Ramos' continued Jekyll and Hyde routine against Atletico or even test Iker Casillas' questionable form.

If Atletico makes it to the next round, they can thank Oblak. If they fail to get out, he surely won't be the reason.