Up against powerhouse clubs from Korea, China and Japan, Adelaide United sit three points clear with a perfect record on top of Group H at the half way mark of the group stage.

The 3-2 win this week was the first time since December 2008 that a United team had managed to come from behind to take all three points and the Reds boss could not have been happier with his team's resolve.

"We got the three points and that was the most important thing," Vidmar said. "Our first half was exceptional and we probably slowed down a little bit in the second half and allowed them to get back into the game.

"But we showed a tremendous amount of character, will and fight to get ourselves back into a winning position. The game should have been over at half time.

"If you look at the whole 90 minutes we created the best clear cut chances, but unfortunately we didn't put them away. We made it difficult for ourselves in the second half.

"But I was really pleased with the way we came back and showed a heck of a lot of fight."

From A-League cellar dwellers to AFC Champions League Group H pacesetters, the contrast has been remarkable.

Vidmar put a significant extent of the change down to the players' work ethic on the training track, and the 'team first' attitude that has spread through the entire squad.

Vidmar specifically heralded the professionalism and conduct of players who have had to bide their time on the bench so far in the ACL including Nigel Boogaard, Cassio, Adam Hughes, Paul Reid, Fabian Barbiero and Adam Griffiths who are all still awaiting their chance.

 "I think we've worked extremely hard, what do they say - luck favours the brave. We've done a hell of a lot of work, the players are up for it, the attitude amongst the group is fantastic, and I've got a heap of praise for those boys who haven't played much...those guys have been tremendous," Vidmar said.

"They haven't had a lot of game time but they have been extremely positive amongst the group and that's helped, when Cassio and Barbiero came on they changed the game for us when we really needed it."

Few would have imagined United to be within touching distance of a place in the second round of the ACL after just three games of the group stage. However Vidmar is not as surprised, considering the belief that is among the playing group and their emphasis that despite three positive results, the job is not done.

"We were sure and everyone was up for believing that we could qualify for the Round of 16, and now we've put ourselves in a great position...but I still believe we need another three points," Vidmar said.

"Three games, three wins is fantastic. We've spoken about it before that we can't get carried away with it, we've just got to get all of our energies together and refocus and make sure we're doing the same things on Tuesday against Hiroshima."

Vidmar and the Reds do not have long to wait before continuing their ACL campaign, with just a six day break before they face Sanfrecce Hiroshima in the reverse tie on Tuesday.

United's squad jets off for Japan today to prepare for the match, and while the Reds have started with the same personnel for all three ACL matches, Vidmar has hinted there could be some changes because of the short turn around.

 "Yeah possibly," Vidmar answered on if any changes were on the cards for the match. "I already started thinking about that last night, so we'll get on the flight  and once we get there we'll see how everyone had pulled up.

 "It has been a tough season but we still need to hang in tough for another six or so weeks. We've got six days to recover, we'll have some light sessions when we get over there, and we should be ready to go again on Tuesday."