With three wins and a draw, So is alone in first place after four rounds at the Gashimov Memorial "super tournament.”

The field is so strong that one of the players said with only a touch of hyperbole that "in this tournament, everyone’s either an ex-world champion, a current world champion or a future world champion.”

"Leading a tournament with three [current or former] world champions … it’s just unbelievable,” So said after Monday’s victory.

So cautioned that a fast start doesn’t guarantee a first-place finish. Indeed, the world No. 8 player faces a tougher lineup in the second half of the tournament than he has so far.

Still, the strong showing represents a rebound from the U.S. championship in St. Louis, where an unexpected visit from his estranged mother and a rare forfeit loss for a rules violation left him with four losses in a subpar performance.

So already has had two notable achievements in the current tournament.

He had his first win over Dutch grandmaster Anish Giri, the world’s No. 7 player who, like So, is considered a possible world champion contender. "I learned a lot from my losses” to Giri, So said.

And So drew his first encounter with former world champion Vladimir Kramnik, now ranked ninth in the world, a game in which So was never in trouble.

So said his struggles at the national championship in St. Louis "motivated me to work harder.” He also said he has been blocking out the critics and "people not really wishing [me] well. I just decided to forget about what people said … and just focus on my games.”

With his win Monday, So has 3.5 points (one point for each win and a half-point for the draw), and leads world champion Magnus Carlsen, alone in second place, by a half-point.

So faces an all-star lineup over his remaining five games, starting with former world champion Viswanathan Anand, No. 6 in the rankings, on Tuesday. After that, he’ll face four more players ranked 13th or better in the world, including the world champion.