After 4 rounds, only 2 players remained undefeated: GM Korchnoi and Klovans
Here are the standings of some of the leaders:
GM Korchnoi, Viktor 2600 SUI 4
GM Klovans, Janis 2433 LAT 4
GM Cebalo, Miso 2505 CRO 3,5
GM Vasiukov, Evgeni 2505 RUS 3,5
GM Jansa, Vlastimil 2482 CZE 3,5
IM Zakharov, Alexander 2395 RUS 3,5
IM Klundt, Klaus 2380 GER 3,5
IM Karasev, Vladimir I 2379 RUS 3,5
IM Boey, Josef 2277 BEL 3,5
Here is the official website. 
Susan as you probably know Victor did very well against almost all World Champions, except Garry Kasparov and I believe that the reason for this was his advanced age. But head to with Fischer I believe Korchnoi was 2-2 with 3 draws, and against Mikhail Tal he simply dominated something like 15-5 and I dont know how many draws.
head*