Bulldogs captain Josh Jackson.

The Bulldogs have their mongrel back in defence but Canterbury skipper Josh Jackson warned his side they need to keep building their combinations to restore their image as the toughest tackling team in the NRL.

Jackson said nobody was more relieved after their breakthrough 20-18 win over the Penrith Panthers on Friday night than Dean Pay, who enjoyed his first win as coach in the Telstra Premiership after taking over from Des Hasler in the off-season.

After breaking their duck for the season, Jackson said the Dogs were solely focused on their round four Good Friday clash with the South Sydney Rabbitohs.

''Our defensive effort particularly in the second half, it wasn't pretty but the boys kept turning up for each other and it's something we can really build on throughout the year,'' Jackson said.

''Tough wins like that you learn a lot on how to win tight games. It's only a starting point. Every week that we play together we build those combinations better.''

Pay's decision to switch Moses Mbye to fullback has proved a masterstroke in the opening three rounds with the 24-year-old leading the competition in line breaks (five) and kick return metres (206).

After struggling to find consistency in the halves, the positional switch for Mbye has given the Bulldogs another option in attack - an area the side lacked under Hasler in 2017.

Bulldogs coach Dean Pay.
Bulldogs coach Dean Pay. ©Gregg Porteous/NRL Photos

''I thought he [Mbye] was fantastic for us, for a guy that is playing in a new position he slotted in really well,'' Jackson said.

''We're happy with what he's doing out the back. He's a good runner and is getting a lot of space with kick returns. He's getting us on the front foots and helping our middle guys out a lot.

''I thought our back five were exceptional on Friday night. They were probably the difference with the work they did.''

Both the Bulldogs and Rabbitohs will meet for the ninth time on Good Friday since 2007 with the Belmore outfit winning five from eight clashes in the annual hit-out.

The Rabbitohs are in a similar position after securing their first victory of the season under rookie coach Anthony Seibold and are bolstered by strike across the park.

''Everyone loves being a part of it,'' Jackson said.

''Souths are coming off a win as well and have got good go-forward in their team. I missed the [Manly-Rabbitohs] game but they've got a dominant forward pack that gets them moving. We'll do our best with [Sam Burgess] and all the Burgess boys.

''Then they've got strike power out wide. It's always a good game, always feeling in it.''