"It was an incredibly difficult decision to join United because my loyalty was with Ngongotaha," he said.
"But United have a clear plan in place for the future and I want to be a part of that. They have a structure for really helping develop players and for me this is best option.
"It's been a fairy tale start. I never expected to have such a good strike record so early on and I hope by the end of the season I've still got a smile on my face.
"I feel really confident at the moment and I'm trying to get goals in games even when I don't get a lot of opportunities which is the sign of a good striker."
The 23-year-old is well on his way to reaching his 20 goal target this season - netting six penalties, five right footed strikes and one with his left.
Willemsen, admitted that he doesn't practice taking spot kicks but said his best goal this season was the "nail biting" penalty against his former side in the recent fiery derby.
Although the game was tinged with disappointment, ending in a 2-1 defeat against their top-of-the-table opponents after they conceded in the final minute of the game.
However it was an "unforgettable match," for the deadly striker who was given the captain's armband after regular skipper - goal keeper Andrew Gibbs was sidelined due to a rib injury.
"I love the pressure, I thrive on it and that's what penalties are all about. Luckily I haven't missed yet, and it's because I have a clear decision made in my head before I strike the ball," he said.
"The goal against Ngongotaha was my best because of the occasion and also I could hear negative comments from their fans on the side-line.
"I was expecting that and used it to spur me on. I sent the keeper the wrong way and it felt great to put us back in the game.
"It wasn't great to lose but we knew they were always going to be the better side because the squad has been together for 10 years. I was just happy to make an impact against my old club."
United must pick themselves up after their two back-to-back defeats which leaves them in third place on 15 points.
Whilst fourth place opponents Cambridge FC are biting at their heels on 12 points with a game in hand which United manager Ian Walker is wary of.
"It's a really big game and if we want to stay in the hunt at the top of the table we need a result," he said.
"It's a long season so we aren't too worried at the moment but we are good enough to get a win.
"Dayne is very dangerous up front and is on a fine run of form and I hope he continues finding the back of the net."
Willemsen, who scored over 100 goals for Ngongotaha, is hoping that his pace and skill will be the edge for his side tomorrow.
"I've been working hard on my speed and I want to make it hard for the Cambridge defence," he said.
"We all want the win to get us back on track so we just need to be switched on from the whistle and I'll be on the hunt in front of goal."
Tomorrow's match Rotorua United against Cambridge FC is at Neil Hunt Park, kick-off 2.45pm.
Tommorow's draw:
WaiBOP Premiership
(kick-off 2.45pm):
Otumoetai FC First Credit Union v Matamata Swifts Prem, Fergusson Park 1
Melville United Prem v Old Blues Prem, Gower Park 5
Katikati FC Ambria Premiership v SGS Papamoa Premiership, Katikati College 1
Rotorua United v Cambridge FC, Neil Hunt Park 1
Tauranga Boys' College 1st XI v Waikato Unicol AFC Prem, Southey 1
Ngongotaha AFC v Tauranga City Premiership, Stembridge Rd 1
WaiBOP Championship
(kick-off 12.30 unless stated):
Otumoetai FC Mens v Matamata Swifts Reserve, Fergusson Park 1
Ngongotaha Champ v Taupo AFC Champ, Stembridge Rd 1
Hamilton Wanderers Champ v Cambridge FC Champ, Porritt Stad 1
Whakatane Town Champ v Old Blues Champ, Rex Morpeth Pk 1
Tokoroa AFC Champ v West Hamilton Champ, Strathmore Pk 1
Te Awamutu Edmond Judd Champ v Waikato Unicol AFC Reserves, The Stadium