The defending champion, 43, put together runs of 69, 80, 69, 65, 143 and 132 to whitewash 25-year-old Yi.
Zhang, who qualified for the tournament with victory in the Shanghai Amateur Masters, had no answer as the Rocket turned on the style, and the five-time world champion will face the winner of Kyren Wilson in the quarter-finals, who beat Xiao Guodong 6-4.
Northern Ireland Open
'Never seen a clearance as good as that' - O'Sullivan hails magic moment from Higgins
17/10/2021 AT 16:43
Earlier, 2005 world champion Shaun Murphy put together the highest break of the tournament – a 136 – as he beat 2018 world champion Mark Williams 6-5.
In a high calibre match, runs of 136, 66, 123, 70 and 56 were enough to see the Magician past Williams, himself who made 69, 54, 63, 98 and 57.

SHANGHAI MASTERS

ROUND 2
Ronnie O'Sullivan 6 – 0 Zhang Yi
Shaun Murphy 6 – 5 Mark J Williams
Jack Lisowski 6 - 3 Mark Selby
Kyren Wilson 6 - 4 Xiao Guodong
ROUND 1
Liang Wenbo 6 – 4 Stuart Bingham
David B Gilbert 6 – 0 Cao Jin
Northern Ireland Open
'Messi can maybe make the game look that easy' - O'Sullivan wowed by Higgins
16/10/2021 AT 21:49
Northern Ireland Open
'Messi can maybe make the game look that easy' - O'Sullivan wowed by Higgins
16/10/2021 AT 21:44