Arsenal manager Arsene Wenger and Manchester United boss Jose Mourinho have both criticised the organisation of the Premier League's fixtures over the Christmas and New Year period.
In particular, the usually bitter enemies have focused their ire on the difference in rest periods afforded to certain teams.
It appears both are perturbed by leaders Chelsea having extra time to rest before their crunch game against fifth-placed Tottenham Hotspur on Wednesday.
The match will come four days after the Blues last played and just over 72 hours since Spurs were in action.
Wenger's Gunners could find the result doubly relevant. They are just about still in the title race, despite trailing Chelsea by nine points. Yet Arsenal also have to be wary about Spurs, who are just one point behind them and threatening to take their longstanding position in the top four away.
Wenger knows the threat and is incredulous at the timing of some of the fixtures bridging the old year with the new, according to BBC Sport.
"In 20 years, it is the most uneven Christmas period I have seen on the fixture front," he said. "The difference of rest periods is absolutely unbelievable; compared to the other teams, it is unbelievable."
The Arsenal chief also took aim at the deals for television rights involving England's top flight, questioning whether the Premier League is even making the decisions: "I don't know any more whether the Premier League is the master of the fixtures. We have to accept that television chooses the games—but I must say on that front that some teams have a bit more luck than others."
Wenger knows his team is under pressure ahead of Tuesday's trip to the Vitality Stadium to face in-form Bournemouth. It comes a mere two days after Arsenal saw off Crystal Palace 2-0 at the Emirates Stadium.
Wenger feels his players' task has been made more difficult: "Every game is so difficult in this Premier League that we go now into a game in 48 hours' time with a big handicap on the fixtures."
Mourinho is unlikely to have any sympathy for Wenger should Arsenal lose to the Cherries. However, the United manager maintains Chelsea and Spurs have been given an edge by the fixtures, per Goal's Nizaar Kinsella.
"It is a match between two amazing football teams with the privilege that no one else has—they are fresh [after a longer break]," he said. "Let's hope for a good match."
Mourinho will keep a keen eye on what the rest has done for Tottenham's freshness. His United side are level on points with Spurs in the race for a top-four finish.
In a rare occasion when Mourinho is united in his thinking with his rival, the Portuguese boss also lamented the challenge of playing games so close together.
"I think it is very difficult to play football in these circumstances, with only 48 hours," he said, per Kinsella. "I think it is amazing for the fans [to have many matches to watch]. Everybody loves the Premier League."
The United manager made clear how being at less-than-peak physical condition affected his players in the first half, according to Kinsella:
When you are not fresh, you play complicated. My team, especially in the first half, made everything complicated. Always taking one touch too many, trying to play through the middle with a lot of people.
Only when I brought fresh people, Mata and Rashford, we got in good positions and had an extra body in creative areas and we deserved to win.
It's difficult to argue with both managers' complaints, even if fans of Chelsea and Tottenham are likely to interpret them as sour grapes. Yet the disparity between rest periods is beyond dispute.
For one thing, it's tough to see the logic behind Chelsea and United playing on New Year's Eve, yet the former getting two extra days of rest. Similarly, Arsenal and Spurs were both in action on New Year's Day, but the Gunners are first up a day earlier than their north London rivals.
What's more, Arsenal go from a home game to an away fixture with just over 48 hours to prepare, although a trip to the south coast is not as daunting as some journeys.
Even though Mourinho and Wenger's gripes are genuine, it shouldn't mean the traditional glut of games needs to be abandoned.
Considering how both managers and players often complain about the workload, this is the one time on the football calendar when the game feels like it's about the fans. The sentiment of putting on extra football that's for supporters, and not necessarily for the millionaires who play it, is an important one amid what can often be considered a cynical modern era.
It would be true to say Mourinho and Wenger have each been involved in the Premier League long enough to be used to these issues by now.
However, both coaches are right to question when the effects of the annual festive fixture congestion don't appear to be the same for all clubs.