SHANNON McDonnell grabbed a hat-trick as Saints finished their Super 8s campaign with a 32-12 victory over Wakefield Wildcats.The treble eased his side to a six-try win and a semi final with Warrington Wolves next Thursday.But they know they’ll have to play a lot better if they are going to progress.After an opening stalemate with handling errors on both sides, Jonny Lomax produced a crucial try-saving tackle on Craig Hall.That was as threatened as either try-line got until Saints opened the deadlock after 20 minutes – Louie McCarthy-Scarsbrook showing great strength to stretch over after a short ball.Luke Walsh kicked the conversion and then almost fashioned another chance for LMS and Jordan Turner on the very next play.But Craig Hall crossed on 27 minutes following some great handling close to the goal line.Both sides toiled to create anything definitive but Saints increased their advantage courtesy of a superb ball from Lomax two minutes before half time.He’d been unlucky earlier in the set with a darting run, but he certainly made no mistake with a long cut out pass for Jack Owens to cross for his sixth of the season.Liam Finn making it a six point game as the hooter sounded with a penalty.Saints thought they’d scored first in the second half as Jon Wilkin and Theo Fages combined to put Joe Greenwood over.But the move was bizarrely called back for obstruction.Wakefield threatened on 50 minutes but a big tackle from Alex Walmsley stopped the threat.Saints then turned defence into attack.Turner found himself free on the left hand side and fed McDonnell on his shoulder.The winger then duly took on Bill Tupou, produced a worldie of a stop start step to bamboozle his opposite number, and flew over from 40 metres.Tom Johnstone finished well on 58 minutes to keep the visitors in the hunt but McDonnell crossed for his second seven minutes later.Again, it was another flowing move – Fages and Turner linking for the winger to pick it up off his bootstraps.His third wasn’t too long in coming either.On 70 minutes Amor put in a barnstorming run to get Saints in field position and McDonnell picked another one off his laces for his hat-trick.Saints had their tails up and completed the match right on the stroke of full time.Amor was again involved; offloading for Fages to show great feet and dart under the posts.Match Summary:Saints:Tries: McCarthy-Scarsbrook, Owens, McDonnell (3), FagesGoals: Walsh (4 from 6)Wildcats:Tries: Hall, JohnstoneGoals: Finn (2 from 2)Penalties:Saints: 6Wildcats: 8HT: 12-6FT: 32-12REF: Joe CobbATT: 9516Teams:Saints: 1. Jonny Lomax; 23. Shannon McDonnell, 4. Mark Percival, 18. Dominique Peyroux, 22. Jack Owens; 3. Jordan Turner, 7. Luke Walsh; 11. Atelea Vea, 28. Morgan Knowles, 10. Kyle Amor, 20. Joe Greenwood, 13. Louie McCarthy-Scarsbrook, 17. Luke Thompson. Subs: 8. Alex Walmsley, 12. Jon Wilkin, 19. Theo Fages, 26. Oliver Davies.Wildcats:21. Max Jowitt; 2. Tom Johnstone, 14. Reece Lyne, 18. Joe Arundel, 3. Bill Tupou; 25. Craig Hall, 7. Liam Finn; 11. Michael Simon, 20. Mikey Sio, 35. David Fifita, 19. Jon Molloy, 17. Matty Ashurst, 13. Anthony Tupou.Subs: 16. Tinirau Arona, 22. Jordan Crowther, 28. Andy Yates, 31. Jason Walton.