On his last day as a teenager — and then again on his first day as a 20-year-old — world champion D Gukesh was reminded that there is still some growing up for him to do. On Thursday, a day before he turned 20, the world champion from India picked up a fight on the board against world no 1 Magnus Carlsen. And lost.

“ Gukesh sometimes plays a bit too ambitiously. He wanted to prove a serious advantage today, which I’m not sure there was,” Carlsen said about his quarry later. “Eventually, he played himself into some trouble. And I took over more and more.”

Even though Friday was a rest day at the tournament, Gukesh turned 20 in the company of fellow grandmasters, including world championship challenger Javokhir Sindarov and Carlsen.…