The firm secured the accolade for its role advising Interflora on the landmark Google AdWords litigation against Marks & Spencer.
On Tuesday, 21 May 2013, the High Court of England and Wales handed down its judgment in the long running case of Interflora, Inc. and Interflora British Unit versus Marks and Spencer plc.
Mr Justice Arnold ruled in favour of Interflora, finding that Marks and Spencer's use of the "Interflora" trade mark as a Google AdWord to advertise its M&S Flowers & Gifts website was trade mark infringement.
Iain Connor, a partner who led the Pinsent Masons team, said: "We are delighted to have won this prestigious award and to have advised on such a significant case which has had and will continue to have an impact on keyword advertising across the world.
"The case broke new ground regarding the evidence required to show consumer confusion, with Pinsent Masons devising a strategy utilising Google Analytics and other online metrics rather than traditional survey evidence."
Pinsent Masons fought off stiff competition from Hogan Lovells, King & Wood Mallesons SJ Berwin, Lewis Silkin, Taylor Wessing and Wragge Lawrence Graham & Co.
The Interflora mandate, secured in 2008, was listed as one of The Lawyer's top 20 cases for 2013 and is a 'first of type' case with implications on keyword advertising across the globe.