Filipino Grandmaster (GM) Wesley So drew with GM Sergey Karjakin of Russia in the eighth round to stay on top in the 2017 Tata Steel Masters Chess Tournament being held in Wijk aan Zee, The Netherlands.
The 23-year-old Cavite pride improved to 5.5 points on three wins and five draws.
GM Pavel Eljanov of Ukraine and GM Wei Yi of China occupied the second spot with five points each after settling for a draw in their respective eight-round matches.
Eljanov split the point with GM Radoslaw Wojtaszek of Poland while Wei halved the point with GM Pentala Harikrishna of India in the tournament which offers +10,000 to the champion and +6,500 to the runner-up
Defending champion GM Magnus Carlsen of Norway dropped to fourth after suffering a crucial eighth-round loss to GM Richard Rapport of Hungary.
With 4.5 points, Carlsen is now in a four-way tie with Karjakin, GM Levon Aronian of Armenia and GM Baskaran Adhiban of India.
Harikrishna and GM Anish Giri of the Netherlands are in eighth with four points apiece while Wojtaszek and GM Dmitry Andreikin of Russia are in 10th with 3.5 points each followed by Rapport and GM Ian Nepomniatchtchi of Russia with three points each and GM Loek Van Wely of the Netherlands with 1.5 points.
Aronian defeated Giri while Adhiban blasted Andrekin.
The game between Van Wely and Nepomniatchtchi ended in a draw.
The tournament organizers will implement a one-day rest before resuming on Wednesday.
Seeing action in the ninth round are So and Aronian, Nepomniatchtchi and Harikrishna, Wojtaszek and Karjakin, Andreikin and Eljanov, Wei and Adhiban, Carlsen and Van Wely, and Giri and Rapport.
To win the tournament, So needs to win or at least draw in his last five games including against Wojtaszek (10th), Andreikin (11th), Wei (12th) and Nepomniatchtchi (13th).