It means Quins go into this weekend's clash with Swansea in second place but level on points with Pontypridd at the top of the table.
New boss Tonkin, who took over at the start of this season, has blended together an exciting squad at The Park, with a number of Wales Under 18 and Under 20 players coming through the ranks.
Add in the likes of Wales Sevens stars Jason Harries, James Davies and Lee Williams and it's certainly an exciting time for supporters of the Quins.
"I'm loving the role so far. It's a dream come true to have a Premiership job like this at my age," said Tonkin, as he reflected on the season so far.
"It's certainly a good start but we're not going to get too carried away with ourselves. We've got a hell of a lot of work to do, especially on our set piece which we know didn't go too well last week.
"But in terms of our start, I'm not surprised to be honest. We always knew we had the ability to win those first three games and luckily we've gone and done that."
Tonkin has been able to call on Wales Under 20 and Scarlets forwards Carwyn Jones and Sion Bennett this season and both start at St. Helen's against Swansea tomorrow. Harries, Davies and Williams also return after a successful trip to South Africa with Wales Sevens.
"We want to get a good mix of young, professional and semi-professional players and that is standing us in good stead so far," said Tonkin.
"We've got some very exciting players coming through as well as our players from Wales Sevens.
"Will Boyde is one I would pick out. He's only a young flanker but he's excelled for us already and has become a leader within the team."
Swansea destroyed the Neath scrum on their way to a derby victory last weekend, props Nicky Thomas and Nicky Smith in fine form. Tonkin knows his side must improve their set piece if they are to keep their unbeaten run going.
"It's going to be a massive test," he said.
"Swansea obviously have some big forwards and their props from Wales Under 20 but we have Ian Jones and Hayd Pugh back from injury so that should help sure up our set piece.
"We're not taking them for granted by any means but we'll have to improve our line-out. That was a poor area for us last week and that's my area of expertise so I was disappointed with that.
"We want to keep this run going and hopefully we might be able to push for a play-off spot. If we get our best 15 out on the pitch we can beat anyone."
Swansea: 15 Nicky J Thomas 14 Andrew Claypole 13 Aled Jenkins 12 Paul Davies 11 Richard Williams 10 Sam Davies 9 Justin James, 1 Tom Sloane 2 Scott Otten 3 Nicky Thomas 4 Teaghan Price 5 Rhodri Hughes 6 Sam Pailor 7 Matthew Davies (c) 8 Tudor Hughes.
Replacements: Paul John, Nicky Smith, Aled Mason, Ben Fox, Rob Dudley Jones, Jake Cole, David Watts, Cameron Clement.
Carmarthen: 15 Howard Thomas 14 Lee Williams 13 Dylan Morgans 12 John Williams (c) 11 Jason Harries 10 Craig Evans 9 Rhodri Wells, 1 Gareth Thomas 2 Ricky Guest 3 Trystan Davies 4 Carwyn Jones 5 Haydn Pugh 6 Sion Bennett 7 James Davies 8 Rory Gallagher.
Replacements: Gethin Robinson, Rhodri Clancy, Javan Sebastian, Luke Joseph, Will Boyde, Christopher Banfield, Panashe Rushesha, Iolo Evans.