Almost an even worse start for Chelsea as Edouard Mendy miscontrols a back pass and luckily for him Joao Felix's first touch takes him away from goal. That could have been 1-0.

Even worse, Mason Mount is booked which means he misses the second leg.

Atletico have a free-kick after about 37 seconds as Mason Mount hacks down the running Joao Felix.

Bayern Munich only have six players on the bench because of injury and Covid so we could well see all five outfield subs come on.

Here we go in tonight's two Champions League games.

Three of tonight's four teams are unbeaten in this season's Champions League - Chelsea (W4 D2), Bayern Munich (W5 D1) and Lazio (W2 D4).

Manchester City are the only other unbeaten team in the competition.

Image source, Reuters

Of keepers to play at least three Champions League games this season, Chelsea's Edouard Mendy has the best save percentage in the competition (94%), only conceding from one of the 16 shots on target he has faced so far.

Chelsea striker Olivier Giroud is averaging a goal every 28 minutes in the Champions League this season - five goals in 142 minutes. Four of those came in his only start - against Sevilla.

Image source, EPA

Lazio boss Simeone Inzaghi has scored 20% of his team's Champions League goals.

He played for the club between 1999 and his retirement in 2010, scoring 15 Champions League goals.

Nine of those came the last time they reached the knockout stages, which was his first season at the club.

Current striker Ciro Immobile has scored eight goals in his nine Champions League starts.

Bayern Munich have won 16 of their 17 Champions League games (drawing one), with an overall goal difference of +48 (61-13) since the start of last season

The defending champions have only failed to score once in their last 27 Champions League matches (0-0 v Liverpool at Anfield, February 2019).

Bayern Munich boss Hansi Flick says his side must return to top form today.

They have won six trophies - a clean sweep - in the past nine months but have dropped points in their last two Bundesliga games.

"We know what has happened in the past days," said Flick. "Against Lazio I want us to be there as a team from the start.

"We have an idea of how we want to play and we have to do that from the start.

"When the Champions League starts we have to be in top form. But looking at the past weeks there have been a lot of matches, a lot of strain on the team and some players missing."

Chelsea were trailing for a total of four minutes during the Champions League group stages, less than any other side. Only Manchester City (one) conceded fewer goals than the London side (two).

Atletico scored only seven goals, the lowest tally amongst the 16 remaining sides.

Image source, Reuters

Chelsea boss Thomas Tuchel is wary of the threat posed by Atletico Madrid striker Luis Suarez.

Tuchel tried to sign Suarez from Barcelona last summer when he was Paris St-Germain boss.

The 34-year-old is La Liga's joint top goalscorer with Lionel Messi - but has yet to have a hand in a Champions League goal this season.

"He is a natural-born striker. He has the certain mentality that only strikers have," said Tuchel. "This mentality to show his will, intensity and anger to score and score and score and is never satisfied."

Atleti boss Diego Simeone said: "Luis generates fear in rivals no matter what competition it is."

Jamal Musiala (17 years and 363 days) is the second youngest player to start a Champions League knockout match for Bayern, after David Alaba at Fiorentina on 9 March 2010.

Image source, Getty Images

Jamal Musiala spent eight years at Chelsea before signing for Bayern Munich and has played for England Under-21s, but the 17-year-old is also eligible to play for Germany.

Musiala was born in Germany to a British-Nigerian father and German mother and then moved to England at a young age.

He was in Chelsea’s academy before joining Bayern in July 2019 and has represented England at under-15, under-16, under-17 and under-21 levels, but also Germany at under-16s.

However, the first country he plays for at senior level in a competitive match will be the nation he represents for the rest of his career.

"Germany are making strong moves, they have made it official they want him in the senior team,” Raphael Honigstein told BBC Radio 5 Live’s Football Daily podcast.

“Low has been to see him in Munich and they are pushing very, very hard. In terms of his identity, he is exactly down the middle having grown up in Germany, then England, and he feels quite attached to England. But he is back in Germany and has all his German team-mates in his ear.

“His mother has told the German FA he is not going to switch again at youth level. If that decision is to be made, it will be made for the seniors. That puts Germany under pressure to put him in straight away, which would then pressure England to fast-track him.

“The German FA were saying they thought they had little chance a few months ago. Now, they feel more encouraged.”

Chelsea's former PSG boss Thomas Tuchel is only the second manager in the history of the Champions League to manage two different clubs in the same season.

Ronald Koeman managed PSV and Valencia in 2007-08.

BBC Sport looks at the reasons behind Diego Simeone's successful 10 years at Atletico Madrid, with the club leading city rivals Real Madrid in this season's La Liga title race.

Atletico have reached the knockout stages of the Champions League for the seventh time in the last eight seasons.

Chelsea are attempting to progress past the last 16 for the first time since the 2013-14 campaign (semi-finalists).

Leon Osman
Former Everton midfielder on BBC Radio 5 Live

Tonight this feels like Thomas Tuchel's go-to side. Yes he can make changes here and there, depending on what's available but I think he trusts these players.

He seems to have come in quite quickly and made one or two big changes, one or two small changes - but he seems quite comfortable with his squad at the moment.

Atletico Madrid boss Diego Simeone on Chelsea counterpart Thomas Tuchel: "We'll be facing a team with a coach that has managed to get every side he has taken charge of to play attractive football.

"He has come to a club that have a lot of financial power and who always make good signings

"This season they've signed some excellent young players and since Tuchel has arrived they've improved their results a lot.

"But their squad speaks for itself, just look at the quality of their three goalkeepers, that proves their power, and their attacking players could get in any team in the world."