Pawn and Two: <sanyas: After 22 moves White seems to have an excellent advantage, but then it all slips away.>
At move 20, Fritz shows an advantage for White of (.67) (20 ply) for the continuation 20.Ke3 h6.
However, White has a better move, 20.Rhc1. Fritz gives an evaluation of (.93) (20 ply) for 20.Rhc1, with the following continuation: 20.Rhc1 Rf8 21.Kg1 Ke7 22.Ne3 Rb8 23.Bd1 Kf7 24.Ng5+ Kg8.
An updated evaluation for this line now shows (.81) (22 ply), with the following continuation: 25.Bg4 Re8 26.Rf1 h6 27.Nf7 Rf8 28.Nd6 Bd7 29.h4 Nd8 30.Rxf8+ Kxf8 31.Rb1.
At this point White advantage starts to slowly increase until White is clearly winning at move 37, (.94) (21 ply) 31...Nc6 32.Rf1+ Kg8 33.h5 Rf8 34.Rc1 Rb8 35.g3 Na7 36.Ng2 Nbc8 37.Nxc8 Nxc8. White is now clearly winning with 38.Nf4 Ne7 39.Bxe6+ Bxe6 40.Nxe6.
Improvements can probably be found for both sides with a deeper search, but White has a clear advantage in this line.
In the game, Black then slips by playing 22...Ke8? Fritz indicates Black best move with drawing chances is 22...Ke7. Fritz gives the following evaluation: (.73) (20 ply) 22...Ke7 23.Raf1 h6 24.Nh3 g5 25.Nf2 Nb5 26.Nd1 Bd7. At this point Fritz's evaluation has dropped to (.62) (18 ply) with the move 27.Rf3 indicated as best.
Then after 22...Ke8?, Fritz indicates Black again slips into a losing position.
At move 23, White erred with 23.Bg4?. Fritz gives an evaluation for this move of (.45) (20 ply) with this continuation: 23.Bg4 Nb5 24.Bxe6 Bxe6 25.Nxe6 Kd7 26.Nf4 Rhf8 27.Rhf1 Naxc3. Black has good drawing changes in this variation.
Instead, White should play 23.Na3!. Fritz gives the following evaluation and continuation for this move: (1.02) (20 ply) 23.Na3! h6 24.Nh3 Rb8 25.Rab1 Nb5 26.Nxb5 Rxb5 27.Rxb5 axb5 28.Bh5+ Kd8.
At this point, White advantage has increased considerably. Fritz gives the following continuation showing White increasing his positional advantage and winning material at move 37: (1.80) (22 ply) 29.Nf4 Nb6 30.Rf1 g5 31.Ng6 Rh7 32.Rf8+ Kc7 33.Nh8 Re7 34.Nf7 Kb8 35.Bg6 Ra7 36.Bb1 Ra4 37.Nxh6.
My conclusion is that White missed a win at move 20, then Black gave him another chance at move 22, and finally White missed at a win for a second time with his 23rd move.