Here's a great video of Karpov and Kasparov in their world championship match in 1987 in Seville. You can see Karpov fidget under pressure although he had the advantage. We all know how that feels, don't we? So you can follow the moves, I am reproducing the position on the board at the point where Karpov played 53. Bh6, attacking Kasparov's queen on f8.
As you can see, Karpov was a rook up for Kasparov's isolated passed pawn and a 2-1 pawn majority on the kingside. Fritz gives white a +-3.83 advantage over black. In the comments section of the video, there was mention about Kasparov losing his queen, and this is actually not the case. The moves went 53. Bh6 Rd3 54. Bf8 Rh3+ 55. Kg2 Rg3+ 56. Kh2 Rg1 57. Bc5 d3. 1-0 . It would be wrong for Karpov to take the rook ( 58. Kg1) because the D pawn will promote. The move here is 58. Bb4.