With just one goal scored in last week's UEFA Champions League semi-final openers, the return legs ought to serve up plenty of drama and intrigue on Tuesday and Wednesday.

Bayern Munich tackle Real Madrid for the 22nd time needing to score at least one goal to salvage their dream of retaining the title, whereas Los Merengues are the only club in the last four able to defend first-leg gains. As for Atletico Madrid, the sole team still unbeaten in the competition, their incredible adventure continues away against a Chelsea side brimming with belief.

First semi-final, Tuesday 29 April
Bayern Munich-Real Madrid (first leg: 0-1)

The scoreline did not tell the whole story during Bayern's 5-2 win against Werder Bremen on Saturday as Josep Guardiola's men put in a Jekyll and Hyde display, labouring in the first half before hitting their stride after the break. The good news was that Franck Ribery seemed to rediscover his form, and the holders have history on their side as they prepare for their 200th European encounter. Bayern have never lost at home to Real Madrid, recording nine wins and a draw, though it is true too that Merengues coach Carlo Ancelotti has never lost to the Bundesliga champions, overseeing five victories and a pair of stalemates. In addition, Cristiano Ronaldo gave himself a timely boost of confidence with two sumptuous long-range efforts in Saturday's 4-0 success against Osasuna. Having now struck 30 Liga goals this term, the reigning FIFA Ballon d'Or winner is back at the peak of his powers.

Player to watch
Iker Casillas
proved in the first leg that he remains one of the best goalkeepers in the world, even if he has been serving as understudy to Diego Lopez in the league. Casillas had just one difficult save to make but pulled it off with aplomb, keeping out Mario Gotze at close range to deny Bayern an all-important away goal. Due to turn 33 on 20 May, he has made 38 decisive saves in the competition this term, putting him top of the list of the keepers still involved, with Bayern's Manuel Neuer a distant second on 30. The Spaniard could well play an integral role as the action unfolds in Munich.

The coaches
Men of honour who have both amassed superb trophy collections, Carlo Ancelotti and Pep Guardiola have one other thing in common – a deep respect for each other. That was evident again ahead of the first leg, when Ancelotti gave his rival fulsome praise. "Guardiola is a great coach who has revolutionised football," he said. "He did it at Barcelona and now he's trying to do the same thing at Bayern, where it is more difficult. But he will get there."

The stats 
– The number of times Bayern have gone through after losing the first leg 1-0 away from home. In fact, they have failed to overturn that deficit just once, against AC Milan in 1990.

4 – The number of times Madrid have progressed after opening a tie with a 1-0 home victory. On the other hand, the Spanish side have exited twice despite building a similar lead, losing 2-0 to Juventus in both 1996 and 2005.

What they said
"We have contested three semi-finals in the last few years, but I think we'll reach the final this time. We'll be facing a similar game in Munich to the one at the Bernabeu, and this tussle will be like an early final," Cristiano Ronaldo, Madrid forward.

"I didn't get the impression that the Madrid officials were happy at the end of the game. They know what awaits them in Munich. I think that, at home, the atmosphere at Bayern resembles an inferno" Karl-Heinz Rummenigge, Bayern chairman.

It's not fair to compare a coach with 15 years' experience to one who's less experienced. That's something I don't like to do.

Chelsea manager Jose Mourinho on his Atletico Madrid opposite number Diego Simeone

Second semi-final, Wednesday 30 April
Chelsea-Atletico Madrid (first leg: 0-0)

Both Atletico and Chelsea enjoyed successful domestic outings between the two legs of their European joust. Los Colchoneros continue to lead the way in the Liga after sealing a vital 1-0 success at Valencia courtesy of a Raul Garcia header, while the Blues reinvigorated their Premier League hopes away against Liverpool. Giving another masterclass in rigour and opportunism, Jose Mourinho's men prevailed 2-0 thanks largely to a slip by Steven Gerrard and a late counter-attack. Despite missing a number of regular starters, Chelsea fielded an ironclad defence at Anfield, with Mark Schwarzer imperious and various stand-ins excelling themselves. Tight at the back and devastating on the break, Atletico and Chelsea boast similar strengths, and the slightest error could prove fatal.

Players to watch
Fernando Torres
, David Villa and Diego Costa are the three most recent players to have tied down the role of lone striker for world champions Spain. Having recently switched his allegiances to La Roja, Costa is almost guaranteed a squad berth at Brazil 2014, whereas Torres and Villa – who will be on opposite sides – are hoping to use the occasion to remind Vicente del Bosque of their talent.

The coaches
Atletico's Argentinian tactician Diego Simeone is a hot-blooded character who never keeps still for long, spending the 90 minutes of a game urging on his team, whipping the crowd up into a frenzy and generally giving way to his passion. Jose Mourinho has the cunning of a fox, meanwhile, with his mastery of the media constantly taking the pressure off his players. He is also an expert at adapting his tactics for every opponent, and rarely lets slip his serene facade. In short, the two men could hardly have more contrasting personalities.

The stats
– The number of times Chelsea have qualified after clinching a goalless draw in a first leg on their travels. The Blues have gone on to lose twice following 0-0 stalemates away from home, most recently after being held to a 1-1 draw at Stamford Bridge by Barcelona in 2009.

2 – The number of times Atletico have recorded a 0-0 draw in an opening leg on home soil. They were able to advance on both occasions.

What they said
"We defended more than we usually do in the first leg. But we are strong at home and I am sure we will be on the front foot," Gary Cahill, Chelsea defender.

"It's difficult to compare the coaches. I'd even go so far as to say it's not fair. It's not fair to compare a coach with 15 years' experience to one who's less experienced. That's something I don't like to do," Chelsea coach Jose Mourinho on Diego Simeone.

Have your say
Will home advantage prove key in this week's second legs? Which sides do you think will prevail