He then defeated Mark Frost and Peter Wright to reach the fourth round, where he played world number 3 James Wade on the main board and lost 9–3.

[6] O'Connor was one of the two Irish qualifiers for the World Grand Prix and missed a dart for the match in the first round against Vincent van der Voort, losing 1–2 in sets.

[12] He struggled for form after this until the first weekend of November when he lost in the last 16 to Mensur Suljović and Gary Anderson in two Players Championships, earning himself £2,000 in the process.

[15] The result helped him finish 24th on the Q School Order of Merit to claim the final place on offer for a two-year tour card.

[21] At the 2015 UK Open, O'Connor overcame Dean Winstanley 5–3, Mark Webster 9–5 and Ian White 9–6 to reach the fifth round of the event for the first time where he played Stephen Bunting.

[23] He saw off Ian White 6–1 and Vincent van der Voort 6–3 to reach his first quarter-final in three years and first in a European Tour event at the German Darts Masters.

[25] O'Connor was unable to advance past the first round of the World Grand Prix for the fourth time as he missed two match darts against Jamie Lewis.

[31] He kicked off 2017 when he defeated Max Hopp, Christian Kist, Keegan Brown, Ritchie Edhouse and Devon Peterson on the way to a quarter final in UK Open Qualifier 1.

O'Connor then had a couple of bad months, with his best result being a Last 32 in Players Championship 12,[40] where he defeated Ronnie Baxter and Paul Harvey before a 6–5 loss to Steve Lennon.

In June 2019, O'Connor alongside Steve Lennon made it all the way to the final of the 2019 PDC World Cup of Darts where they eventually lost to Scotland 3–1.

[46] In September 2022, O'Connor reached his second European Tour final, losing 8-3 to Joe Cullen in the 2022 Hungarian Darts Trophy, after beating the likes of Nathan Aspinall, Michael Smith and Dimitri Van den Bergh in earlier rounds.

[48] O'Connor was joined by a new playing partner for the Republic of Ireland for the 2023 PDC World Cup of Darts with Keane Barry replacing Steve Lennon.