Barca beat Leo Beenhakker's Madrid side 2-1 in the Spanish Supercopa second leg in September 1988, although Real claimed the trophy after winning the first match 2-0 at the Santiago Bernabeu. The Dutchman's side then embarked on an unbeaten run that has stood unchallenged until now in Spanish football.
It began with 10 straight wins, starting at Oviedo in La Liga, before victories against Norwegian side BK Moss (in the European Cup), Zaragoza, Valladolid, Barcelona, Murcia, Celta, Polish team Gornik Zabzre (home and away in Europe) and Celta Vigo. Then came back-to-back draws versus Athletic Bilbao and Sevilla, ahead of wins against Atletico, Cadiz, Espanyol, Elche and Malaga.
A 1-1 tie at Valencia followed, before a 2-1 win at Elche in the Copa del Rey (which Madrid would win in 1988-89, along with La Liga) and a 1-1 draw in the return at the Bernabeu. Beenhakker's side then thrashed Sporting Gijon 5-1 in La Liga and days later took part in a thrilling 5-5 draw with the Asturian side at El Molinon in the Copa.
After that was another draw away to Real Sociedad, with wins against Sporting (in the Copa) and Betis, prior to a 1-1 tie at PSV Eindhoven in the European Cup and a 2-1 success against the Dutch side in the quarter-final second leg at the Bernabeu, wins over Oviedo, Zaragoza and Valladolid in the Primera Division, Celta in Copa, and a goalless game at Camp Nou.
Then came a 1-1 draw at home to AC Milan in the European Cup semi-final first leg (Madrid would later lose the second game 5-0) and a 3-0 win over Murcia in what was to be the final game in the impressive streak, which came to an end with a 2-0 loss at Celta on April 15. Real had last been beaten on September 29, six and a half months earlier.
The remarkable run actually featured 35 matches and not 34, although the away match against Osasuna in Pamplona was suspended after 43 minutes with the scores at 0-0 after objects and firecrackers were continuously thrown at Madrid goalkeeper Paco Buyo. The two teams replayed the fixture in May in a game that finished 1-1, and the original fixture is not counted as part of Madrid's unbeaten tally.
Beenhakker led Real to three league titles in his three-year tenure, winning the Copa del Rey and the Supercopa in 1988-89, his most successful season at the Bernabeu, and he said this week: "The most important thing, apart from having great players like Hugo Sanchez, [Emilio] Butragueno, Michel and [Jose Antonio] Camacho, was having a very complete team.
"There was hardly any movement in terms of players coming and going. We played for two or three years with roughly the same side. And that helps to create a strong team."
That team won five straight league titles between 1985 and 1990 and is fondly remembered as the Quinta del Buitre, yet the Dutchman's name is rarely recalled. It was a time, however, when Madrid were winning league titles year in, year out, a far cry from their current troubles in the Primera Division.
"[Winning one league title in eight years] has no relation to the greatness of Real Madrid," he said of Los Blancos' recent difficulties in the Primera Division. "I don't know the details, but they need calm, intelligence and credibility to form a great team."
Indeed, it is Barca dominating La Liga these days and Luis Enrique's men equalled the mark set by Beenhakker's side with their 2-1 win at home to Sevilla on Sunday. The Catalans last lost on October 3 in a 2-1 defeat to the Andalusians at the Sanchez Pizjuan - exactly five months ago.
Since then, there have been victories versus Rayo, Eibar, Villarreal, Madrid (4-0 at the Bernabeu no less), Real Sociedad, Betis, Granada, Athletic, Malaga, Atletico, Levante, Celta, Sporting, Las Palmas and Sevilla again in La Liga, with wins over BATE Borisov (home and away), Bayer Leverkusen and Arsenal (away) in the Champions League.
There were also two successes en route to lifting the Club World Cup against Guangzhou Evergrande and River Plate in December, as well as Copa del Rey wins versus Villanovense, Espanyol (home and away), Athletic (at Camp Nou and San Mames) and Valencia (a 7-0 thrashing of Gary Neville's side).
In total, 28 wins (compared to 25 by Beenhakker's side) and just six draws: Villanovense and Valencia away in Copa, Leverkusen in their last Champions League group game with the section already won, plus Valencia, Deportivo La Coruna and Espanyol in La Liga.
Luis Enrique's side have also scored many more goals than Madrid's 1988-89 vintage (102 to 86) and conceded fewer (19 compared to Real's 36), although football changed dramatically in the 17 and a half years since Beenhakker's team started their own special streak in 1988. Both runs are extraordinary in their own way.
"The record means nothing," Luis Enrique said after the win over Sevilla. "If we don't win anything, it will be mean very little. If we win trophies, it will mean much more."
The Asturian coach, who was emerging as a talented youth player at Sporting in 1988-89, before representing Real and then Barca, has always insisted that these marks matter only if trophies follow and is reluctant to take any credit for his side success. However, he and his players can create another little piece of history on Thursday.