Madrid will be the centre of the football world this week when Real Madrid hosts Bayern Munich and Atletico Madrid welcomes Chelsea in the Champions League semifinals.

The oversized personalities of Pep Guardiola and Jose Mourinho dominated Spanish football for half a decade until first Guardiola, then Mourinho, moved abroad.

Now both managers return to Madrid as Mourinho's Chelsea plays at Atletico on Tuesday followed by Guardiola's Bayern visiting Madrid on Wednesday in the opening leg of their semifinals.

With 14 European Cups between them, Madrid vs. Bayern is the standout matchup and has the added element of nemesis Guardiola coming back to Santiago Bernabeu, where he never lost in seven visits as Barcelona coach.

Chelsea's game has its own managerial subplot as Mourinho faces rising talent Diego Simeone, whose Atletico made sure Mourinho finished his contentious last season at Madrid without a title by winning the 2013 Copa del Rey final.

Here are five things you should know about the Champions League semifinals:

Hopeful hosts

Both Real Madrid and Atletico Madrid enter their matches on respective highs, hopeful they can take the first step toward setting up a city derby in the European final in Lisbon. Madrid is still basking in the afterglow of its Copa del Rey title win last Wednesday, when Gareth Bale went a long way toward justifying his record (euro)100-million transfer by scoring the winning goal against Barcelona after sprinting half the pitch. "It's a dream come true," Bale said. "We've won the first of the three available titles and we have to keep fighting for everything." Atletico, meanwhile, ground out its eighth consecutive win in the Spanish league on Friday to move to within three wins of its first league title since 1996.

Ronaldo's return?

Even though Gareth Bale has proven he can pick up the slack for the injured Cristiano Ronaldo, Real Madrid is hoping its leading scorer will be fit to face Bayern Munich. The Ballon d'Or winner has missed Madrid's last four games but has returned to training. Ronaldo has 14 goals in the Champions League and needs just one more to set the record for the most in a season in Europe's top-tier competition. Bayern chairman Karl-Heinz Rummenigge hopes Ronaldo will be fit. "The semifinal is a great spectacle that will be watched all over the world," Rummenigge said. "So the best players should also play."

Price of priority

After winning the Bundesliga with a record seven games to spare, Bayern Munich stumbled to a draw and two losses before it beat Eintracht Braunschweig 2-0 on Saturday. Bayern's loss of form can be explained in its desire to repeat last season's unprecedented treble, with attention now firmly on the Champions League and German Cup. "The Bundesliga is over for us. Our target is the Champions League," Guardiola said after clinching the domestic title.

Courtois' allegiance

Goalkeeper Thibaut Courtois finds himself in the curious situation of playing both for and against his "two teams" when Atletico Madrid hosts Chelsea. Courtois plays for Atletico, but his mother club is Chelsea, which has loaned the 21-year-old Belgium international out for the past three seasons. Courtois is one of the big reasons Atletico has only lost one of the 28 games it has played at Vicente Calderon Stadium this season.

Mourinho's semifinal woes

Chelsea manager Jose Mourinho is a serial semifinalist in the Champions League -- he is coaching a team at this stage for the fifth straight season -- but getting beyond the last four has proved troublesome for him of late. He lost in the semifinals in all three years at Madrid from 2011-13, and in his first spell at Chelsea between 2004-07, the London club was knocked out twice by Liverpool at this point. Mourinho has won the competition twice, however, with FC Porto in 2004 and Inter Milan in 2010 and is seeking to become the first coach to win it with three different teams.

AP writers Steve Douglas in London and Ciaran Fahey in Berlin contributed to this report.