The Black Eyed Peas star knocked Jessie J, who had held the top spot for the past three weeks, into second place.
Danny O'Donoghue and Tom Jones retained last week's positions of third and fourth.
Over on Britain's Got Talent, the four judges were unmoved in their search rankings from last week, with David Walliams leading again, from Amanda Holden, Simon Cowell and Alesha Dixon.
In the battle between the two shows, The Voice yet again extended its lead over Britain's Got Talent and last weekend scored over 100% more searches than its ITV rival.
The most searched-for contestant on The Voice on Saturday was Jaz Ellington, scoring four times as many Yahoo! searches as Paige Turley, the popular Britain's Got Talent contestant.
However, Bo Bruce is still the most-searched contestant over the four weeks of this year's shows.
Watch Simon Cowell compare Britain's Got Talent to The Voice below:
Photo gallery - The Voice UK's coaches and teams rehearse with the Battle Advisors: