Emma Raducanu has been photographed looking glum after flying back to London following her recent defeat in the first round of the US Open. The 21-year-old was sent crashing out of the competition by Sofia Kenin, with critics quick to take aim at the Briton in the time since. Raducanu finally broke her social media silence on Saturday, with the tennis star posting for the first time since her US Open exit. And the Daily Mail have now obtained pictures showing Raducanu looking glum as she went for a walk in the London rain. The 21-year-old walked with her hood up and swearing pink shorts as she…