Midfielder Alexia Putellas celebrated being named The Best FIFA Women's Player earlier this week by scoring a 91st-minute winner as Barcelona left it late to beat Real Madrid 2-1 and reach the final of the Spanish Supercopa.
An inspired performance from Madrid goalkeeper Misa Rodriguez looked set to take the tie to extra-time when Putellas fired home in stoppage time to extend Barca's winning streak to 29 games in all competitions.
The tight encounter sets the stage for March, when the teams will meet three more times, first in the league and later in the Champions League, with the second leg of the Clasico quarterfinal due to be played at a sold-out Camp Nou.
Before then, Barca will meet the winners of Thursday's other Supercopa semifinal between Atletico Madrid and Levante in Sunday's final.
Jonatan Giraldez's Barca side, who completed a historic treble last season but lost on penalties to Atletico in the Supercopa semifinal, were the better team in the first half against Madrid without ever really getting going.
Barca forward Fridolina Rolfo saw an early chance saved by Misa at the near post and later headed over.
Misa also made two fine saves from Patri Guijarro before Lieke Martens headed over as Madrid made it to the break at Las Rozas, Spain's national team headquarters, with the game still goalless.
The one-way traffic continued into the second half. Jenni Hermoso shot wide after a flowing Barca move before Madrid finally posed some questions at the other end.
Claudia Zornoza came closest for Los Blancos, thumping the woodwork from distance, but there was not much more work for Sandra Panos in the Barca goal.
As Barca pushed for a winner, they continued to find Misa in their way. She tipped an Alexia effort wide and then made another great stop from Irene Paredes' header.
However, with the game heading for an additional 30 minutes, Misa could do nothing about Alexia's clinical finish after substitute Asisat Oshoala had hit the post.
It capped another special week for Alexia, who followed up winning the Ballon d'Or in December by winning FIFA's The Best on Monday.
Her goal against Madrid was her 19th of the season.