Aronian hurries to get rid of the bishop pair.
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. c1d2 This is considered to be one of the  most harmless continuations against the Nimzo-Indian, but it was used in  the past by Alekhine. 4... e8g8  5. g1f3  5... c7c5  6. a2a3  6... b4c3  7. d2c3  7... f6e4  8. a1c1  8... b7b6  9. g2g3  9... c8b7  10. f1g2 