"I did not want to alienate the clubs and tire out our players.
Brown had the Belgians watched as they surprisingly slumped to a 4-1 defeat in Scandinavia.
And the Scotland manager was in Dublin himself to see the Croats fight back from 2-0 down to steal a draw thanks to an injury-time Davor Suker penalty.
Croatia visit Hampden Park then Scotland travel to Brussels to face Belgium on World Cup duty next month.
Brown told BBC Radio Scotland's Off The Ball programme: "I think the result flattered Croatia. I think they were here for the Guinness in the first half.
Wee bit indecision
"Their back three are very experienced, two playing in Italy and one in the Bundesliga, but they were ripped apart in the first half.
"I think if we get in about them then they are vulnerable at times.
Brown saw signs that Croatia's recent change of coach could assist Scotland.
"They are a wee bit indecision," he said. "They started with three at the back and later changed to a back four.
"So I don't think he knows his favoured shape and, when there's indecision by the coach, it goes in to the mind of the players and hopefully that is the case here.
"When Prosinecki came on, they clicked into gear and I am sure he will play at Hampden and be pulling the strings.
"They have a couple of top-class strikers. They are electric and we will have to be at our best."
Optimistic about it
Brown had no regrets about passing up the opportunity to play a warm-up game himself.
"Our league has already started and Rangers and Celtic have important games next week in the Champions League," he said.
"I did not want to alienate the clubs and tire out our players.
"I am hoping that it was the right decision and I think it was."
Scotland cannot afford to drop another point in their three-way battle with Belgium and Croatia.
But Brown said: "I am optimistic about it. Cautiously so, but I do think we have a good chance.
"We have no inferiority complex against Croatia and we have not lost for the last nine away games and don't intend to in Belgium."
Scotland could yet face the Republic in a World Cup play-off should both countries finish runners-up in their qualifying sections.
"I thought they were excellent and I can see why they are top of their group," Brown said of the Irish performance.
Converted a penalty
The Republic had gone ahead after 21 minutes through Damien Duff and Clinton Morrison added the second after 78 minutes.
But Davor Vugrinec's header brought Croatia back into the game before Suker's equaliser.
Liverpool's Jari Litmanen made one and converted a penalty for Finland in Helsinki.
Goals from Mikael Forssell and Joonas Kolkka had the Finns three up within half an hour, Bart Goor pulled one back for Belgium before the break, but Hannu Tininen completed the home side's victory 12 minutes from the end.
Another of Scotland's other Group 6 opponents were in action, Latvia losing 1-0 at home to the Ukraine.