Stefano Pioli and Jose Mourinho confirmed their status as Serie A's best coaches by leading Milan and Roma to silverware last season, according to former Rossoneri and Giallorossi boss Fabio Capello.
Capello also claimed Inter's prospective move for Romelu Lukaku represents a "blow" for the rest of the Italian top flight, given his dominant displays during his successful first spell with the Nerazzurri.
While Pioli became the first Milan boss to win the Scudetto since Massimiliano Allegri in 2010-11 last month, Mourinho ended Roma's 14-year trophy drought by winning the Europa Conference League in his first season with the club.
Capello, who led Milan to four Serie A titles in five seasons between 1991 and 1996 before masterminding Roma's most recent Scudetto triumph in 2000-01, hailed the duo's achievements as he declared next season will be make-or-break for many of the division's other top coaches.
"The best? Pioli and Mourinho," he told Il Messaggero.
"The first brought Milan back to success, the second confirmed himself as an international coach. Jose achieved a very important success.
"[Juventus coach] Allegri, [Lazio's Maurizio] Sarri and [Napoli's Luciano] Spalletti paid for their return to Serie A. They were granted a transitional season. Now will be the moment of truth."
Meanwhile, with Inter reportedly set to re-sign Lukaku less than a year after his club-record £97.5million move to Chelsea, a series of Italian football's biggest names have spoken about his expected impact.
Milan legend Alessandro Costacurta said on Sunday the deal would make Inter title favourites, while Gianfranco Zola claimed the Belgian will make a "huge impact" for Simone Inzaghi's men after he scored 30 goals for the Nerazzurri in the 2020-21 campaign.
Capello concurred with those views, adding: "Lukaku is a great blow because in Italy, no one is able to mark him because of his excessive physical power."
However, while Milan are expected to work with a smaller budget than their rivals as they look to defend their crown, Capello hailed their recruitment policy and revealed his confidence that they can compete once more.
"I don't put my mouth on the market because these topics are the responsibility of the coaches," he added.
"The experience of recent years leads me, however, to say that we must have confidence. At Milan, they have learned how to handle things, and they know how to choose [players]."