The Bavarians burst out of the blocks in what was a virtually flawless display by the defending league champions.
Diaz struck inside the first minute to give them a very early lead and they never looked back.
Harry Kane continued his prolific form in the 27th minute with his 18th Bundesliga goal in just 10 games this season before Diaz wrapped up proceedings with his second of the game in the 84th minute.
Bayern rarely looked in danger of conceding all game in a very impressive performance.
Elsewhere in the Bundesliga on Saturday, Samuel Mbangula's second-minute strike was enough to hand Werder Bremen a 1-0 win over St Pauli, while Yan Couto (23') and Christoph Baumgartner (7') traded goals in the 1-1 draw between Borussia Dortmund and RB Leipzig.
Bayer Leverkusen looked to be getting back to form in their 2-0 win over Union Berlin, with Ernest Poku (33') and Christian Kofane (33') providing the goals.
Augsburg overcame Wolfsburg 3-1 to move out of the relegation zone and above them on the league table.
Noahkai Banks opened the scoring in the third minute before Mert Komur doubled their advantage six minutes into the second half.
Robin Fallhauer added the third in the 63rd minute before Adam Daghim pulled one back for Wolfsburg just two minutes later.
Borussia Dortmund and Hamburger SV were the big winners in a dramatic Bundesliga round, as Dortmund beat TSG Hoffenheim 2-0 at the Westfalenstadion and Hamburg edged SV Werder Bremen 3-2 in a Nordderby at the Volksparkstadion.
Saturday proved to be a goal-fest in the Bundesliga as the top two sides in the standings blew away their opposition to pull further away from the rest.
VfB Stuttgart will aim to maintain their strong home record when they host Bundesliga leaders Bayern Munich this weekend.
Aleix Garcia is enjoying the best spell of his career, turning himself into a key figure in Bayer Leverkusen's midfield and pushing for a place in Spain's 2026 World Cup squad.
