1...Bg4!
Black eschews the equality arising from 1... Rxa7 and exploits his lead in development
2.d4exd3
3.Qxd3Rd8
Black organises his firepower
4.Qe3+
Now, if 4... Be7, then 5.0-0, and White can breathe a little easier, but Black decides that his queen is not needed...
4...Qxe3+
5.fxe3Rd1+
6.Kf2Ne4#
Kuimin-Grob (1961)