visayanbraindoctor: 25. Nd5 is a super GM move, a World Champion's move. A kind of move only an Alekhine can even think of and actually bring into fruition. Not because of itself as it is (a clearance sacrifice for the e4 square), but because AAA probably had to imagine it in his chess mind when he played
Note that at this juncture, AAA was allowing the superficial 'threat' of Rxd1. If he retakes with his rook, his a2 pawn is left hanging, and to take with his Bishop, he concedes the d-file to Black. In addition, AAA was inviting Black to 'trap' his Bishop at g5 with f6.
So AAA had to calculate all the nuances of conceding his d-fie and recovering his 'trapped' Bishop even from the starting position of 17. Ne3.
At 24... ab5 chess spectators must already have been wondering why Alekhine had conceded the initiative to Keres, one of the most dangerous attacking masters in chess history; and at this point in time probably the leading World Championship contender after AVRO 1938. Black controls the d-file with the 'threat' of Rd2, and the c8-h3 diagonal with the 'threat' of Bxh3. Then boom... 25. Nd5!
I wonder if that shocked even the great Paul Keres, conqueror of 9 World Champions, bete noire of tactical wizard Mikhail Tal, and the only master of his generation to dominate Victor the Terrible Korchnoi.
For some reason Alekhine got a second wind in the years 1941 to 1942. I think he was playing the best chess in the world during these two years of his last swan's song. Had he and Botvinnik met in a WC match in 1942, i would place my bet on Alekhine winning.