Overall, the 32-year-old has scored 39 goals in all competitions for Real this season, and also set up another 12 strikes for his teammates. Villarreal will play at Valencia, and Real Sociedad visits Celta.
If Real Madrid's Cristiano Ronaldo has proved anything this season, it is that we're living in his era.
The ill feeling increased when Celta were denied a penalty for a handball by Raphael Varane towards the end of the first half which saw Aspas booked for dissent.
The Welshman has lifted the trophy twice since completing his then world record breaking £86m move from Tottenham in 2013.
Celta, with nothing left to play for, improved after conceding the first goal and started to threaten, with Aspas creating a series of chances. Both calls were debatable and will fuel conspiracy theories always rampant in Spain at this time of the year, although in this observer's view the referee's decisions were understandable.
Guidetti, who came within inches of sending Celta to Stockholm for the Europa League final, cut through the disappointment with a deft finish from a Pione Sisto assist.
The Frenchman went with the same side that withstood an Atletico Madrid revival to book their place in the Champions League final a week ago.
A draw in Malaga this weekend and a victory against Juventus in Cardiff next month would give Madrid its first double since 1958, when Raymond Kopa and Alfredo Di Stefano were leading the team. And boy, has that plan worked out perfectly.
Zidane kept normal starters such as Karim Benzema, Casemiro and Luka Modric out of the starting lineup against Sevilla on Sunday, when Real Madrid won 4-1.
However, ten minutes in the visitors were in front as the ball dropped on the edge of the area, with Cristiano Ronaldo shifting it on to his left foot and smacking home an unstoppable effort.
"We still have the most hard job ahead of us", he said in the Spanish press on Thursday morning. It was deadly finishing of the highest quality. Madrid won La Liga and the Europa League in 1985-86, but their last season with both a La Liga and Champions League crown (then European Cup) title was almost sixty years ago.
The ex-Manchester United striker is the new all-time top scorer in Europe's big-five leagues - the Premier League, La Liga, Serie A, Bundesliga and Ligue 1 - with 368 goals. However, Zinedine Zidane had a positive report on Gareth Bale's injury situation in his press conference and reported that the Welshman was back in training.