Bareev today qualified by drawing the last game against Judith Polgar. I was a bit disappointed that Judith didn't try the King's Indian, but the line she played also created some chances.
For Peter Leko it is interesting that Bareev plays some of the same openings that Leko's first round opponent Gurevich does. This has the advantage that Peter is well prepared against those openings. It also has the disadvantage that Bareev can take a look at the games between Leko and Gurevich and use that information.
Leko - Bareev
The last couple of games between the two always saw the same French that Gurevich plays with 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 dxe4. It is good that Peter indeed has prepared the other important line against the classical French with 4.e5, as we could see in game three against Gurevich.
Of course Bareev may continue to play the Caro-Kann, as he did against Judith Polgar. Against the Caro-Kann Peter usually plays the main line, as Polgar did in the first game against Bareev.
Apparently Polgar wasn't able to prepare something good against Bareev's 17..Rd5 (see my analysis in the game three preview). Leko must have something ready against this, if he plays 1.e4, or play some other line against the Caro-Kann.
Of course Peter also has the option of playing 1.d4, against which Bareev uses the Slav most of the time. Peter won one nice game against Gelfand last November in the Slav, but Bareev will have much more experience with this opening than Peter.
Bareev - Leko
Bareev has played the Queen's Indian against Polgar.
He has also frequently played the classical Nimzo-Indian. Interestingly, this is another line that was discussed in the Gurevich - Leko games, and Peter's preparation looked very strong there. Bareev has even played a couple of games with the same endgame that was discussed in the Gurevich - Leko games, specifically with the line played in game four. Unless Bareev finds something good against the 16..f5 Peter used there, I expect Bareev will continue to use the Queen's Indian.
In game two, after
1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.g3
Polgar played the same
that Leko plays. Bareev replied with the interesting
5.Qc2 c5 6.d5
that only last year found its way into top-level chess, after the introduction of the gambit
6..exd5 7.cxd5 Bb7 8.Bg2
It would be interesting to see this line discussed in the match. As the line is still very new, there should be room for improvements on both sides.