Leksand reached the quarterfinals after beating Austrian Klagenfurt.
Frölunda defeated German Mannheim in his eighth.
Tonight, the two met in the first of two CHL quarterfinals.
And it was a fast-paced first period.
Leksand struck in the first period when Max Veronneau scored the 1-0 goal.
But Frölunda picked up the disadvantage less than a minute later via Patrik Carlsson and then Jens Olsson scored the 2-1 goal for the Gothenburg team.
17-year-old Lian Bichsel made it 2-2 for Leksand shortly afterwards.
Bichsel, who has been selected in the preliminary squad for the JVM for Switzerland, scored his first league goal.
- We make a good first half with a good atmosphere in the team and lots of chances.
It's so fun to score my first goal in a professional league, the Swiss tells SVT after the first period.
Three quick goals in the third
It was a goalless second period.
But in the third, Frölunda's Stefan Elliott struck with his backhand to 3-2.
In a short time, two more Frölunda goals came from Patrik Carlsson and Elmer Söderblom.
5-2 was also the end result.
Now Frölunda has the advantage before next week's decisive quarter final at home in Gothenburg.
The third Swedish team in the CHL quarterfinals, Rögle, beat Sparta Prague on Tuesday.
That match also ended 5-2.
On Thursday, Leksand and Frölunda meet in the SHL. The decisive quarter final in the CHL takes place in Gothenburg on 14 December.