[2] A week later, he qualified for the 2011 PDC World Darts Championship after defeating Stephen Byrne to win the Tom Kirby Memorial Irish Matchplay.

[6] He represented Northern Ireland alongside Brendan Dolan in the 2012 PDC World Cup of Darts and together they reached the quarter-finals, where they were defeated by the Netherlands 4–0, having beaten Denmark in the second round.

[14] In his second World Cup of Darts with Brendan Dolan the pair were beaten 4–5 in the last 16 by the Croatian duo of Robert Marijanović and Tonči Restović.

[16] Mansell beat Co Stompé and Conan Whitehead to face Michael van Gerwen in the fourth round of the UK Open, which he lost 3–9.

[20] Mansell beat Ben Burton and Dean Stewart to reach the third round of the 2014 UK Open but there lost to James Wade 9–1.

[21] In June, Mansell and Dolan beat Peter Wright and Robert Thornton from Scotland in the quarter-finals of the World Cup of Darts.

[26] Mansell's four World Cup appearances in a row ended in 2016 after Daryl Gurney overtook him as Northern Ireland's second highest player on the Order of Merit, behind Brendan Dolan.

[30] On 15 December 2022, at the 2023 PDC World Championship, Mansell beat Ben Robb but was defeated in the second round by Peter Wright 3–0 in sets.

At the 2024 Grand Slam of Darts Mansell reached his first major semi final by defeating Cameron Menzies 16–15 in a deciding leg in the quarter-finals.