The X Factor Australia winner rises from two to one after previously spending a fortnight at the top, pushing LMFAO's 'Sexy And I Know It' into second place.
Meanwhile, Taio Cruz jumps from seven to five with 'Hangover', Jason Derulo's 'Breathing' holds at nine, and Flo Rida slips from eight to ten with 'Good Feeling'.
Further down the chart, Snoop Dogg and Wiz Khalifa jump from 13 to 11 with 'Young, Wild & Free', while Jessica Mauboy's 'Galaxy' climbs 21 to 19.
Timomatic vault 39 to 22 with 'Set It Off', Bruno Mars lifts 33 to 24 with 'Count On Me', and Matt Corby's 'Into The Flame' rises 40 to 33.
The Top 10 singles in full (click where possible for our reviews):
1. (2) Reece Mastin: 'Good Night'
2. (1) LMFAO: 'Sexy And I Know It'
3. (4) Lloyd ft. Andre 3000 and Lil Wayne: 'Dedication To My Ex (Miss That)'
4. (3) Ed Sheeran: 'The A Team'
5. (7) Taio Cruz: 'Hangover'
6. (6) Guy Sebastian: 'Don't Worry Be Happy'
7. (10) Coldplay: 'Paradise'
8. (5) Rihanna ft. Calvin Harris: 'We Found Love'
9. (9) Jason Derulo: 'Breathing'
10. (8) Flo Rida: 'Good Feeling'
Watch the music video for 'Good Night' below: