Match in brief
Chelsea were a constant menace early on and Thibaut Courtois had already denied Timo Werner from point-blank range before Christian Pulišić darted in behind the Madrid defence and rounded the goalkeeper to open the scoring in the 14th minute.
Madrid were awoken though and Karim Benzema led the fightback, clipping the post from 20 metres then hauling his team level with a thumping volley following Éder Militão's flick-on.
Both sides were more wary after the interval with Zinédine Zidane's men noticeably more diligent defensively. Substitute Hakim Ziyech tested Courtois from a free-kick and Toni Kroos' skidding effort fizzed just wide but a third goal in the game rarely looked like materialising.
Player of the Match: N'Golo Kanté (Chelsea)
"His work in attack and defence was spectacular. He gave balance to the team. He recovered balls in all areas and made great passes between the lines to enable quick transitions. A great game."
Joe Walker, Real Madrid reporter
All said and done, it's a decent result for Madrid, especially given the start they made – looking second best for long periods. Benzema's stunner clawed them back into a match they had no right to still be in, and from there they grew in confidence. Of course, they need to score in London next week, but considering what might have been, they probably would have taken a 1-1 draw.
Jon Phipps, Chelsea reporter
Chelsea just seem to get more and more impressive under Tuchel, and this was further proof of what a team they are becoming. Save for failing to deal with the corner that allowed Benzema to score, this was almost the perfect night for Chelsea, who were a threat going forward and solid at the back. The excellent away goal from Pulišić means they have an advantage to take home to London, so it's all set up for a cracking second leg.
Raphaël Varane, Real Madrid defender: "I think we saw two different games, in the first half and the second. They started well with a lot of intensity and they pressed us well; they broke our first line of the press with some very vertical play. With Karim's goal we got into the game and the second half was a lot better."
Zinédine Zidane, Real Madrid coach: "We wanted to press high one on one, but when you don't carry it out well, things are tough. Once we scored, we were better and controlled play a lot more. We're alive and we're going to the second leg with the idea of winning. In general, we're happy with tonight."
César Azpilicueta, Chelsea defender: "We started really well. The first 20–25 minutes, we got the goal and could have scored more. We started with courage and we knew we had to play at our best level. We missed that last pass where we could have chosen the best option."
Thomas Tuchel, Chelsea manager: "Unfortunately they scored from a set piece but there was nothing else for us to defend – we did not allow any chances. It was a bit of a disappointing result at half-time and important that we stayed calm and didn't lose confidence. The speed, the intensity dropped and you could feel that we were a bit tired. We have to live with 1-1."
• This was Real Madrid's 450th game in European Cup/UEFA Champions League history.
• Pulišić is now the outright highest-scoring American in UEFA Champions League history – with five goals – and the first to strike in a semi-final.
• Benzema notched his 71st UEFA Champions League goal, moving him level with Raúl González in fourth place on the all-time top scorers list.
• Benzema (33 years, 129 days) became the oldest scorer for Madrid in a UEFA Champions League semi-final, taking the record from Cristiano Ronaldo (32 years, 86 days).
• Madrid have kept just two clean sheets in their last 13 UEFA Champions League home games.
Real Madrid: Courtois; Éder Militão, Varane, Nacho; Carvajal (Odriozola 77), Casemiro, Kroos, Modrić, Marcelo (Asensio 77); Benzema (Rodrygo 90), Vinícius Júnior (Hazard 66)
Chelsea: Mendy; Christensen, Thiago Silva, Rüdiger; Azpilicueta (James 66), Jorginho, Kanté, Chilwell; Pulišić (Ziyech 66), Mount, Werner (Havertz 66)
Madrid have Osasuna at home in the Liga at the weekend, while Chelsea are at home against west London neighbours Fulham. This tie concludes on Wednesday 5 May, with the winners taking on Paris or Man. City in the final in Istanbul on 29 May.