Pospisil, the current world number 129, produced arguably the performance of his career as he took advantage of a series of uncharacteristic mistakes from the Briton to claim a 6-4, 7-6 win at the Indian Wells Tennis Garden.

The 26-year-old broke the Sir Andy serve four times during the match as he recorded his first-ever victory over the three-time Grand Slam champion.

"I felt like a big result was coming, because I believe in my abilities, but just kind of had to put the pieces together again," the Canadian said. 

"Obviously to beat the number one player in the world is incredible. 

"I mean, it’s the biggest win of my career, and I’m just thrilled right now."

Pospisil's opponent in the third round is scheduled to be Dušan Lajović of Serbia.

It proved to be a difficult day for some of the seeded players in the men's tournament as Jo-Wilfried Tsonga of France, ranked seventh, was beaten in three sets by Italy's Fabio Fognini 7-6, 3-6, 6-4.

Croatia's Ivo Karlovic, the 19th seed, also crashed out at the second round stage as he lost 6-4, 6-3 to Yoshihito Nishioka of Japan.

Third seed Stanislas Wawrinka, another three-time Grand Slam winner, had no such trouble as he swept aside Paolo Lorenzi of Italy 6-3, 6-4.

In the women's event, Venus Williams of the United States defeated Jelena Janković of Serbia in a battle of the veterans as she progressed by virtue of a 1-6, 7-6, 6-1 win.

Angelique Kerber of Germany, in line to become the world number one after the conclusion of the tournament owing to the withdrawal of Serena Williams, is also through after she beat compatriot Andrea Petkovic 6-2, 6-1.