Star three-quarter Rene Ranger faces an inquisition over a white and yellow card issued in the last moments of the game as a result of his attempted tackle on Bull Bjorn Basson.
Lam had only nine backs available to him before the game and can ill afford to drop to eight ahead of Friday's game against the Stormers in Cape Town.
However, the victory, the first in an opening game on a South African leg of the season was the first in nine years and only the second time the Bulls had lost at home in three and a half years.
"I'm proud of the effort the boys put in. We should have won in the first round [against the Crusaders] but we were disappointing last week [in Hamilton]. The boys all know that.
"But we worked out a game plan while we were overnighting in Sydney on the way over and we selected the team accordingly to achieve that. It was a big win for us," he said.
The kicking game the Blues employed was crucial while they also looked to defuse the Bulls kicking game. And in defence it was a case of knocking their big men over by being ruthless at the tackle and breakdown.
The Blues had been penalised heavily during the first half and Lam was clearly bemused by the officiating noting that in four Super Rugby games played on the day there appeared to be variations in interpretations. But the Blues just had to adapt to what they were dealt with in Pretoria.
"Overall the main thing was getting the result," he said.
Lam said Gareth Anscombe's effort at first five-eighths and in scoring all 29 points had been an 'outstanding effort'.
But the team had shown a lot of discipline to stay within the game plan devised.
"No matter which way the game goes you need to get the basics right," he said.
Lam said it had been the Blues intention to run the ball, from within their own 22m area, when it was on rather than kicking to the Bulls for them to bring it back up and look for a Blues mistake.
"We were moving the ball to other channels [out wide] to kick. We trained a lot in our own half during the week. And I don't mind if guys are trying something we have talked about and mistakes happen," he said.
Lam said Pretoria police were dealing with a fan who threw a bottle and hit Blues captain Keven Mealamu after the game.