The white queen is under attack and the simple retreat 27.Qc3 would have won. But Giri finds a winning aggressive sequence.
27.Ng6+
Kg8
28.Rxf5!
Qd3
[28...Rxe5
29.Rxf8+
Kh7
30.Rh8#
]
29.Qe6+!!
A clincher! [29.Qe6+!!
Kh7
30.Nxf8+
Rxf8
31.Qg6+
Kg8
32.Rxf8+
Kxf8
33.Qxd3
and white mates soon.] 1-0