Nice Puzzle from a Recent Game

While poking around one of this Blog’s readers named “Peter” who has an interesting site called dollyknot I came across Leonard Barden’s Column in the London Evening Standard.  He gives the following position from Axel Rombaldoni v Mikhail Gurevich, Cappelle 2012 which I found really tricky.  Barden writes, “as White's small material edge is offset by Black's far advanced passed pawn. Rombaldoni had calculated accurately, however, that White (to play) can win decisive material here by force. How did he do it?”

White to move

Highlight for solution:  1.Rb7 Kg7 2.Bc4 b2 3.Rxf7+ Kg6 4.Rf1 (or 4.Rb7)