After winning all five of their games so far this season and securing a bonus point in each, Llandovery stand two points clear of Pontypridd at the head of the table.
And they will be looking to continue this impressive run of form against Llanelli tomorrow although Lewis argues the visitors will start as favourites.
"Llanelli have been one of the outstanding performers in the league since it has been running. They are a quality squad and have got a number of professional players so we will be underdogs," he said.
"When you look at the squad they've got, our players have a lot to prove. Anything can happen in a local derby but hopefully we can put in a good performance."
The Drovers' start to the season has certainly been impressive but one which has not surprised Lewis.
"We are pleased with how well it's gone so far but as for being surprised, I wouldn't say that," he added.
"We have had this group of players for the last three years now and we showed glimpses of what we could do last year by finishing in the top four. We want to push on but we'll keep our feet on the floor, there's a long way to go."
Llandovery scrum-half Rhodri Williams will again be the main danger to the opposition defence and he is joined at half-back by James Garland who replaces Cerith Rees at number 10.
Elsewhere, Lyndon Lewis makes a number of changes as he keeps his side fresh for one of their biggest tests of the season. Chris Knight comes in for Jake Randall on the right wing while Matthew Jacobs moves from outside centre to the left wing. But Lewis reserved special praise for Williams who has enjoyed a flying start to the season.
"He's an outstanding prospect and been a real threat in all our games so far. I've seen no one better so far this season. We'd all like to see him in a Wales jersey one day," he said.
Llanelli make nine changes themselves for their visit to Church Bank and will be led by the experienced Adam Powell.
Head coach Anthony Buchanan welcomes back Wales U20 international Owen Williams after injury while Johnny Lewis reverts back to inside centre after doing a fine job in the pivotal role last week.
Wales U18 backs Connor Lloyd and Steffan Hughes are replacements along with tight head Jamie Kaijaks who returns from injury.
"Llandovery have worked hard over several seasons and are now reaping the rewards. This will be our fifth away match from seven so we are not in a bad position," said Buchanan.
"We had a very tough match last week against Cross Keys and we are expecting the same at Church Bank. It's going to be another exciting and entertaining Principality Premiership match and a regional shop window for all players."
Llandovery: 15 Lee Rees 14 Chris Knight 13 Adam Warren 12 Jack Roberts 11 Matthew Jacobs 10 James Garland 9 Rhodri Williams, 1 Owen Evans 2 Adam Yelland 3 Pete Edwards 4 Shaun Jones 5 Bryn Griffiths 6 Phil Day (c) 7 Shaun Miles 8 Richard Brooks.
Replacements: Andrew Jones, Wyn Jones, Luke Kendall, Lloyd Phillips, Llewellyn Jones, Thomas Ball, Rob Walters, Sam Soul, Cerith Rees.
Llanelli: 15 Jordan Williams 14 Kristian Phillips 13 Nic Reynolds 12 Johnny Lewis 11 Chris Keenan 10 Owen Williams 9 Justin James 1 Rhys Thomas 2 Kirby Myhill 3 Aled Hopkins 4 Adam Powell (capt) 5 Jake Ball 6 Ed Price 7 Duane Eager 8 Stuart Leach
Replacements: 16 Tom Sloane 17 Tomos Wilson 18 Nathan White 19 Nathan Hart 20 Connor Lloyd 21 Steffan Hughes 22. Kyle Evans 23 Jamie Kaijaks
Referee: Ian Davies