Marcelo Bielsa's side are building towards their Premier League opener against Manchester United on August 14, while Betis will start their La Liga campaign away to Mallorca on the same day.
The Whites also beat Guiseley 3-2 on Tuesday, although the fixture was largely an Under-23s affair, with head coach Bielsa deciding to keep his first-team players back for the clash with Blackburn.
Leeds will take on Fleetwood Town on Friday night before tackling Real Betis the next afternoon, with the Premier League club, as mentioned, facing four matches in the space of five days.
Bielsa's side will round off their preparations for the new season with a friendly against Ajax on August 4 before facing Man United at Old Trafford on the opening weekend of the new Premier League campaign.
Junior Firpo and Jack Harrison have both joined Leeds this summer, with the latter completing a permanent move from Manchester City, while the club have also brought in youngsters Lewis Bate, Amari Miller and Sean McGurk ahead of the new season.
Betis, meanwhile, opened their pre-season with a 4-0 victory over FC Winterthur on July 17 before suffering back-to-back 1-0 defeats to Wolverhampton Wanderers and Derby County in their last two fixtures.
The Seville outfit will complete their preparations for the new season with a friendly against Roma on August 7 before opening their La Liga campaign away to Mallorca on August 14.
Los Verdiblancos impressed in Spain's top flight last term, finishing sixth, meaning that they have automatically qualified for the group stage of the 2021-22 Europa League.
It is difficult to know exactly what to expect from the Leeds XI considering that the Whites will be in action against Fleetwood on Friday night.
Firpo made his debut against Blackburn following a summer move from Barcelona, and the left-back is expected to retain his spot in the side, with Luke Ayling potentially operating at right-back.
William Carvalho, who represented Portugal at this summer's European Championship, is also available and could now start, having been used off the bench against Derby last time out.
New signing Sabaly is in line for another start at the back, while Kike Hermoso, who is training with the first team this summer, may again feature in the middle of the defence.
Leeds United possible starting lineup:
Meslier; Ayling, Llorente, Koch, Firpo; Klich, Rodrigo, Roberts; Raphinha, Bamford, Harrison
Real Betis possible starting lineup:
Silva; Sabaly, Ruiz, Hermoso, Miranda; Guardado, Carvalho, Camarasa; Fekir, Moron, Canales
We say: Leeds United 1-1 Real Betis
This will be another competitive match for Leeds, who are packing in a lot of football in the final stages of July. The Whites will believe that they can cause plenty of problems to their Spanish opponents, but we fancy a low-scoring draw on Saturday afternoon.