Real Madrid fans ready for Kroos farewell party at sold-out Bernabeu
But the shock retirement announcement of midfielder Toni Kroos (34) on Tuesday suddenly changed the significance of Saturday's clash, which quickly lost that end of the season vibe.
Under the spectacular new Santiago Bernabeu roof, a sold-out crowd will bid farewell to a fan favourite and all-time club great who will be playing his last game at the stadium after a remarkable decade with the Spanish giants.
Germany's Kroos said in a statement on his social media that his final match for Real will be next week's Champions League final, adding that he will retire after this year's European Championship on home soil.
Kroos' farewell party could add another distraction for Real Madrid, who have had little to play for in the last couple of weeks, having claiming a record-extending 36th LaLiga title on May 4 and reached the European Cup final by beating Bayern Munich in the semi-finals four days later.
Carlo Ancelotti has rested most of his regular starters in the last three league matches but is expected to use the Betis game as a dress rehearsal for the Wembley final, with two big question marks in defence.
Goalkeeper Thibaut Courtois' full recovery from an ACL tear suffered in August has left the Italian with a tricky decision.
Stand-in Andriy Lunin was Real's penalty hero as they beat Manchester City to reach the semis but the 31-year-old Courtois is widely considered one of the best keepers in the world and is likely to regain his starting spot against Dortmund.
The centre-back who will play alongside Antonio Ruediger is the other issue Ancelotti has to decide on.
He has used holding midfielder Aurelien Tchouameni and long-time back-up defender Nacho alongside Ruediger after David Alaba and Eder Militao sustained ACL tears early in the season.
After making a full recovery last month, Brazil's Militao has struggled to regain top form and, with Tchouameni out with a foot injury sustained against Bayern, Ancelotti is left to decide between the Brazilian and Spaniard Nacho.
Champions Real Madrid have 94 points, 12 ahead of second-placed Barcelona, with the season's surprise package Girona and Atletico Madrid completing the top four who will represent Spain in next season's Champions League.
Fifth-placed Athletic Bilbao and Real Sociedad in sixth have qualified for the Europa League, while Betis, who are seventh, will play in the Conference League.