Albury coach Adrian Purtell says his team must improve to have any chance in next Sunday's away blockbuster against Southcity after a mistake-riddled win over Junee on Sunday.
Thunder's defence was again outstanding, but the home team blew some chances in a 38-12 win, with hard-running second-rower Liam Wiscombe scoring a first half hat-trick.
"We dropped too much ball, we've got to focus on that this week, but we're going to enjoy our win," Purtell said.
"We've got a big challenge and we can't give teams too much ball, especially against Southcity, who are just another level in competition, so we have to improve without a doubt."
Thunder's win left it just 13 points short of gaining the competition lead.
Both Gundagai and Thunder are unbeaten after playing out a 28-all draw in the opening round.
The premiers have a points differential of plus 88, while the Thunder is plus 76.
Junee started the round in eighth position, but a superb long pass set up Rusiate Kaliseiwaqa in the fourth minute.
The visitors had a chance to go further ahead, but dropped the ball over the line, with Luke Ingram levelling the scores shortly after with a typical bumping run.
Wiscombe produced a barnstorming 25m run to grab the lead, before one of the more bizarre tries you will ever see.
Star Diesels' fullback Daniel Foley put up a towering kick and Ingram bumped him over, with the visitors winning a penalty where the ball landed.
Quick-thinking hooker Trent Schubach scurried to the mark, took a quick tap with fullback James Girdler the only player in a position to stop him.
The Diesels had the lead, but that was their last points.
Another crashing Wiscombe effort saw the home team regain the lead after 35 minutes and he repeated the feat right on half-time for a 20-12 lead.
The Diesels tried desperately to slow the play down as Thunder rattled on three more tries after the break, with Curtly Jenkinson posting a 75m effort.
Jenkinson was terrific, posting 18 points from a double and five goals, while hard-running centre Etu Uaiseke was superb, making a match-high 11 tackle busts.
Robbie Byatt plays like a front-rower in a halfback's body, consistently taking on the bigger men, while English front-rower Brad Nicholson pulled off a couple of big hits as he led the strong defence, which is a good sign ahead of premiership fancies Southcity and Tumut in the next fortnight.
"That's something that's been really good all year," Purtell said.