Pep Guardiola and Jurgen Klopp united to fight for a U-turn to the Premier League's three-substitution rule after Manchester City and Liverpool played out a 1-1 draw on Sunday.
A share of the points between the sides that have combined to win the title for the past three seasons leaves Liverpool in third just a point off the top, while City sit five points further back in 11th but with a game in hand.
A flying start from Liverpool was rewarded with Mohamed Salah's 13th-minute penalty, but Gabriel Jesus levelled for Guardiola's men before City captain Kevin De Bruyne pulled a penalty wide three minutes before half-time.
After a pulsating first 45 minutes, the tempo eased off in the second with Liverpool suffering an injury blow when Trent Alexander-Arnold was forced off with a calf problem.
Guardiola and Klopp have been outspoken advocates of the use of five substitutes, which was used in the Premier League at the end of last season and is being used in all other major leagues in Europe and the Champions League this season.
However, the Premier League's top teams lost a vote for it to remain for the 2020/21 season with fears it only serves to benefit the clubs with bigger squads.
"We speak about how we have to fight again and again about five substitutions," said Guardiola when asked about the subject of his post-match conversation with Klopp.
"All around the world there is five substitutions. Here we believe we are a special league with just three players, we don't protect the players.
"Look at Trent Alexander-Arnold, an international English player, he is injured. That's why it is a disaster.
"With this calendar which comes from a special year before, I will demand, if the people allow my voice, five substitutions have to come back for the players, the managers, everyone to do it. If not, it's difficult to sustain it."
Klopp accused Premier League CEO Richard Masters of a "lack of leadership" over the matter. "It's not an advantage, it's a necessity," added the Liverpool boss.
- Klopp's front four -
Klopp's brave team selection with Diogo Jota joining Roberto Firmino, Salah and Sadio Mane in a front four was rewarded with a blistering start from the defending champions.
Salah smashed home from the penalty spot to open the scoring after Kyle Walker upended Mane.
"It was a super football game form all points of view," said Klopp. "Two top teams ready for a massive fight. The energy of both teams tonight was incredible. After 10-15 minutes everybody was already breathing heavily."
City, though, managed to compose themselves after going behind and pick the holes in the two-man Liverpool midfield that Klopp's attacking approach left exposed.
Jesus showed why City have missed a natural striker for most of the season with both he and Sergio Aguero sidelined by injury, producing a stunning finish to level on 31 minutes.
The Brazilian flicked De Bruyne's driven pass beyond Alexander-Arnold before prodding beyond his international teammate Alisson Becker.
City were now in the ascendancy as De Bruyne drilled a low shot inches wide, but the normally brilliant Belgian let Liverpool off the hook just before half-time.
Joe Gomez was penalised for handling inside the area after a VAR review. But De Bruyne missed his first penalty for four years when he pulled his spot-kick wide of the target.
The second period failed to match the thrilling end-to-end pace of the first, but it was City who had more control and the better openings.
Jesus headed a golden opportunity wide before De Bruyne saw another sighter fail to dip in time from the edge of the box.
"In the second half we had a more clear chances but a draw is a fair result," added Guardiola. "Against teams like Liverpool if you concede a penalty you should avoid and miss a penalty, it makes it more difficult."