The chief executive, Karen Blackett, the managing director, Claudine Collins, and the chief operating officer, Josh Krichefski, talk about the win, which was announced last Thursday.
Although not together when they found out, Krichefski admits that the leadership team were all "emotional" when they heard the news.
Collins added: "We were at different places, but when we found out on email, each one of us said we'd actually cried. We couldn't believe it."
Blackett said: "It's been an intense year, but it has been an amazing year. We've had a year of organic growth of existing clients, we've had a year of pitching for new clients and a year of hanging on to existing clients.
"There has been some amazing work we've done. It has been an amazing year."
Watch MediaCom's full response in the video above.