“It was very difficult for me and there’s a lot of pressure, but it’s good for me and this is a big moment in this season,” said Zhao.
“I just tried to control myself but I didn’t do it very well and hopefully in the next round I can do a lot better.”
Highfield, who has lost in the first round on four occasions, said: “He played great in the first half of the second session and that took a bit of wind out of my sails.
“You don’t play at the Crucible every day. I’ve only ever played four matches here in my life and the pressure gets on you and there’s a big crowd.
“It’s always great to be here. It is an amazing place to play and every time you play here you cherish it.
“But I’m proud of myself to be here from where I was a year ago when I was trying to get back on the tour.
“At times I thought he looked edgy and I got him on the ropes, and I let him off and he will punish you because he is that good.”
Northern Ireland’s former world number one Mark Allen is 3-5 behind against China’s Zhang Anda, with their second session to come on Sunday morning.
Three-time champion Mark Williams secured a 6-3 lead over 22-year-old Antoni Kowalski, the world number 69 and the first player from Poland to play at the venue.
Before play started BBC presenter Hazel Irvine said Virgo was “universally loved by everyone in this sport and beyond – he really was the voice of snooker”.
On Thursday there was a memorial service for Virgo in his home city at Sheffield Cathedral, a short walk from the Crucible.
“The cathedral was packed and we gave John a wonderful send-off as he was a very special man,” 1985 world champion Dennis Taylor told BBC Radio 5 Live.
“I knew him for more than 50 years and he was a great all-round entertainer. There’s a big gap here in the Crucible this year with John not being with us.”
