The 50k walker smashed his personal best time by more than two minutes to cross the line in a time of 3.55.01.
Brendan finished 29th overall and it will provide a great platform for his next appearance in the Olympics – hopefully in Brazil in four years time.
The pace was set from a very early stage in what looked like blistering heat around the streets of London.
Brendan’s team-mate Rob Heffernan, who recorded a new national record, finished a terrific fourth place just outside the medals.
Brendan is expected to come home to Donegal where he is expected to receive a huge welcome.
“I was delighted with how I did; I mean I smashed my personal record and finished in the top 30, so I’ve got to be very happy with that,” said the Milford man.
Well done Brendan – you did us all proud.