Ivanchuk started with a draw against Hikaru Nakamura of United States and then crushed Vallejo, outplayed Anand and won a see-saw battle against Levon Aronian of Armenia.
The only disappointing result for Ivanchuk, who is fondly called ''Chuky'', in this tournament so far has been the loss at the hands of Carlsen.
But with five rounds still to come, anything is possible. The new time-zone in Bilbao and different climate could bring in huge change in fortunes as well, especially, when one knows that Ivanchuk's chess depends on his mood.
As things currently stand, Ivanchuk is on 10 points which is three more than Nakamura, who is on second spot. Anand, Aronian and Carlsen share the third spot on six points apiece while Vallejo Pons is at the bottom of the table having just garnered three points.
Nakamura picked Vallejo as his first victim in the fifth round to nose ahead. Aronian showed much promise but possibly the unexpected loss against Ivanchuk put him off and Carlsen went down from a winning position against Vallejo Pons.
Overall, its been an exciting week for the players and the heat is likely to build up further when the caravan settles down in Bilbao.
Standings after round 5: 1. V Ivanchuk (UKR, 10); 2. H Nakamura (USA, 7); 3-5. V Anand (IND), M Carlsen (NOR), L Aronian (ARM) 6 each; 6. F Vallejo Pons (ESP, 3).
PTI