The slugger described an “incredible performance” in the second leg as Arsenal knew Chelsea would give them a fightback.
Goalkeeper Daphne Van Domselaar returned to the starting eleven and produced a stellar performance, denying Sam Kerr on several occasions in the second half.
England defender Lotte Wubben-Moye starred in the absence of Leah Williamson and Arsenal suffered no blow when fellow centre-half Steph Catley went off with a calf injury at the end of the first half.
In-form striker Alessia Russo was full of tricks and flicks. The England international usually has minimal touches of the ball, but when the pressure was on she did what was necessary to avoid difficult situations.
Slagers said his team was willing to “suffer” to get what they wanted and it paid off in the end.
He said, “It’s a pain to do something you love. I think the team performed really well. They were prepared for a difficult scenario and a change of pace.”
“In the first 15 minutes, probably towards the end of the game when things changed again, they just stayed in the ‘controlled middle’, as we call it.
“They stayed in the game and were constantly in control in any scenario or tempo change. They did their job. Mentally we were in control.
“Obviously, we wanted to prevent them from getting chances and in an ideal world there wouldn’t be any shots, but it was two really good teams going against each other.”
Former England captain Steph Houghton said Arsenal were “better in the big moments” and deserved to progress on the balance of competition.
Brighton forward Fran Kirby said: “Arsenal allowed Chelsea to have the ball, they were comfortable in their blocks and worked really hard defensively.
“The opportunities they had they could have gone on and won the game, so they will be really proud of the performance.
“It showed a different side of Arsenal. It showed what they can do when they have to defend.”
Arsenal will be hoping to book their place in the final when they take on the winner between Lyon and Wolfsburg – who play each other on Thursday night.
The final will take place on 23 May in Oslo, Norway.
