During this tournament commentators and pundits began affectionately referring to Kellett as the 'cocky craftsman' (in a nod to Eric Bristow), due to his confidence on-stage in comparison to his otherwise humble nature off it.
He overcame Peter Wright, Colin Lloyd, Dave Chisnall, Robert Thornton and Andy Hamilton en route to the final, where he lost 6–4 to three-time world champion John Part.
[13] He also made his debut at the World Grand Prix and missed one dart for the first set in the opening round against Raymond van Barneveld and was beaten 2–0.
[14] Kellett won a qualifying place for the Grand Slam of Darts by beating Steve Brown 5–3 and was whitewashed 5–0 by Taylor in his opening Group A game.
[18] He played in a last leg decider against Gary Anderson, having led 4–1, and missed a dart at tops to complete a 120 finish for the match to lose 6–5.
[19] He took the first of sixteen spots available to non-qualified players through the 2013 ProTour Order of Merit for the 2014 World Championship and faced Paul Nicholson in the first round, losing 3–0.
[22] Kellett was beaten 9–4 by Terry Jenkins in the third round of the UK Open and failed to qualify for another PDC major during the rest of the year.
[30] At the 2016 UK Open Kellett defeated Nathan Aspinall 6–5, Joey ten Berge 9–7 and Michael Smith 9–5 to reach the fifth round of the event for the first time, but lost 9–5 to amateur Barry Lynn.
[31] He failed to carry this last 16 showing into the rest of the year though, as he was knocked out in the first round of two European Tour events and reached the last 32 of three Players Championship tournaments, but lost each time.