Twenty20 Bowling Against Each Opponent by Kevin O'Brien
| Opponent | Balls | Mdns | Runs | Wkts | BB | Ave | 4wI | 5wI | SRate | Econ |
| Afghanistan | 174 | 0 | 287 | 8 | 4-45 | 35.87 | 1 | 0 | 21.75 | 9.89 |
| Antigua Hawksbills | 12 | 0 | 29 | 1 | 1-29 | 29.00 | 0 | 0 | 12.00 | 14.50 |
| Auckland | 6 | 0 | 15 | 0 | | | | | | 15.00 |
| Australia | 18 | 0 | 18 | 1 | 1-18 | 18.00 | 0 | 0 | 18.00 | 6.00 |
| Bangladesh | 54 | 0 | 71 | 2 | 1-23 | 35.50 | 0 | 0 | 27.00 | 7.88 |
| Barbados Tridents | 12 | 0 | 6 | 2 | 2-6 | 3.00 | 0 | 0 | 6.00 | 3.00 |
| Barisal Burners | 36 | 0 | 50 | 3 | 2-31 | 16.66 | 0 | 0 | 12.00 | 8.33 |
| Bermuda | 12 | 0 | 14 | 0 | | | | | | 7.00 |
| Canada | 36 | 0 | 60 | 0 | | | | | | 10.00 |
| Canterbury | 6 | 0 | 15 | 0 | | | | | | 15.00 |
| Central Districts | 24 | 0 | 38 | 0 | | | | | | 9.50 |
| Chittagong Kings | 42 | 0 | 54 | 2 | 1-18 | 27.00 | 0 | 0 | 21.00 | 7.71 |
| Derbyshire | 48 | 0 | 75 | 2 | 1-27 | 37.50 | 0 | 0 | 24.00 | 9.37 |
| Dhaka Gladiators | 42 | 0 | 66 | 2 | 1-28 | 33.00 | 0 | 0 | 21.00 | 9.42 |
| Durham | 66 | 0 | 71 | 6 | 2-14 | 11.83 | 0 | 0 | 11.00 | 6.45 |
| Duronto Rajshahi | 36 | 0 | 34 | 4 | 3-17 | 8.50 | 0 | 0 | 9.00 | 5.66 |
| England | 18 | 0 | 22 | 2 | 2-22 | 11.00 | 0 | 0 | 9.00 | 7.33 |
| Essex | 60 | 0 | 109 | 3 | 2-32 | 36.33 | 0 | 0 | 20.00 | 10.90 |
| Glamorgan | 6 | 0 | 8 | 0 | | | | | | 8.00 |
| Gloucestershire | 6 | 0 | 15 | 0 | | | | | | 15.00 |
| Guyana Amazon Warriors | 18 | 0 | 28 | 1 | 1-14 | 28.00 | 0 | 0 | 18.00 | 9.33 |
| Hampshire | 12 | 0 | 15 | 0 | | | | | | 7.50 |
| Hong Kong | 54 | 0 | 79 | 4 | 3-32 | 19.75 | 0 | 0 | 13.50 | 8.77 |
| India | 54 | 0 | 93 | 4 | 3-40 | 23.25 | 0 | 0 | 13.50 | 10.33 |
| Jamaica Tallawahs | 30 | 0 | 32 | 5 | 4-22 | 6.40 | 1 | 0 | 6.00 | 6.40 |
| Jersey | 6 | 0 | 9 | 0 | | | | | | 9.00 |
| Kent | 24 | 0 | 39 | 0 | | | | | | 9.75 |
| Kenya | 36 | 0 | 34 | 3 | 2-15 | 11.33 | 0 | 0 | 12.00 | 5.66 |
| Khulna Royal Bengals | 24 | 1 | 13 | 1 | 1-13 | 13.00 | 0 | 0 | 24.00 | 3.25 |
| Lancashire | 18 | 0 | 31 | 1 | 1-11 | 31.00 | 0 | 0 | 18.00 | 10.33 |
| Middlesex | 24 | 0 | 18 | 1 | 1-18 | 18.00 | 0 | 0 | 24.00 | 4.50 |
| Namibia | 74 | 0 | 88 | 3 | 2-21 | 29.33 | 0 | 0 | 24.66 | 7.13 |
| Nepal | 24 | 0 | 8 | 3 | 3-8 | 2.66 | 0 | 0 | 8.00 | 2.00 |
| Netherlands | 78 | 0 | 93 | 7 | 3-26 | 13.28 | 0 | 0 | 11.14 | 7.15 |
| New Zealand | 24 | 0 | 31 | 0 | | | | | | 7.75 |
| North West Warriors | 54 | 0 | 59 | 3 | 2-14 | 19.66 | 0 | 0 | 18.00 | 6.55 |
| Northamptonshire | 66 | 0 | 80 | 1 | 1-15 | 80.00 | 0 | 0 | 66.00 | 7.27 |
| Northern Knights | 30 | 0 | 39 | 2 | 2-33 | 19.50 | 0 | 0 | 15.00 | 7.80 |
| Oman | 48 | 0 | 54 | 4 | 2-25 | 13.50 | 0 | 0 | 12.00 | 6.75 |
| Otago | 6 | 0 | 17 | 0 | | | | | | 17.00 |
| Papua New Guinea | 66 | 0 | 46 | 5 | 2-10 | 9.20 | 0 | 0 | 13.20 | 4.18 |
| Scotland | 99 | 0 | 117 | 8 | 3-35 | 14.62 | 0 | 0 | 12.37 | 7.09 |
| Somerset | 42 | 0 | 64 | 1 | 1-25 | 64.00 | 0 | 0 | 42.00 | 9.14 |
| Sri Lanka | 6 | 0 | 9 | 0 | | | | | | 9.00 |
| Sri Lanka A | 12 | 0 | 15 | 0 | | | | | | 7.50 |
| Surrey | 17 | 0 | 21 | 1 | 1-21 | 21.00 | 0 | 0 | 17.00 | 7.41 |
| Sussex | 36 | 0 | 40 | 2 | 2-22 | 20.00 | 0 | 0 | 18.00 | 6.66 |
| Sylhet Royals | 36 | 0 | 37 | 0 | | | | | | 6.16 |
| Uganda | 12 | 0 | 7 | 2 | 2-7 | 3.50 | 0 | 0 | 6.00 | 3.50 |
| United Arab Emirates | 120 | 0 | 121 | 8 | 3-14 | 15.12 | 0 | 0 | 15.00 | 6.05 |
| United States of America | 6 | 0 | 2 | 1 | 1-2 | 2.00 | 0 | 0 | 6.00 | 2.00 |
| Warwickshire | 21 | 0 | 31 | 1 | 1-31 | 31.00 | 0 | 0 | 21.00 | 8.85 |
| Wellington | 30 | 0 | 33 | 1 | 1-25 | 33.00 | 0 | 0 | 30.00 | 6.60 |
| West Indies | 42 | 0 | 41 | 3 | 2-17 | 13.66 | 0 | 0 | 14.00 | 5.85 |
| West Indies XI | 54 | 0 | 78 | 3 | 1-14 | 26.00 | 0 | 0 | 18.00 | 8.66 |
| Worcestershire | 24 | 0 | 29 | 0 | | | | | | 7.25 |
| Yorkshire | 48 | 0 | 54 | 4 | 3-27 | 13.50 | 0 | 0 | 12.00 | 6.75 |
| Zimbabwe | 18 | 0 | 26 | 0 | | | | | | 8.66 |