RB Leipzig's director of sport Ralf Rangnick says new signings are set to follow after the Bundesliga club secured direct qualification in next season's Champions League on Saturday.
RB Leipzig capped a superb first Bundesliga campaign as strikers Timo Werner and Davie Selke scored twice in their 4-1 thrashing of Hertha Berlin.
Leipzig, founded by energy drinks giants Red Bull in 2009, only reached Germany's top flight this season after four promotions in seven years.
They are second only to champions Bayern Munich in the table and are certain to finish in the top three, which means a direct path into the Champions League group stage.
With Red Bull's billions behind them, Rangnick says RB are set to open the cheque book to recruit for their Champions League debut.
"When we play in the Champions League, we'll have to strengthen the squad," said Rangnick, 58, before kick-off in Berlin.
"The whole thing of course will have to take into account the requirements of financial fair-play.
"Whether three or four new additions will be enough, I do not know, perhaps we'll need five or six and we need more quality across the board."
Leipzig have won 20 of their 32 games in Germany's top tier.
They are the first club since Kaiserslautern in 1998 to qualify directly for the Champions League immediately after promotion to the Bundesliga.
"No one could have anticipated that we would have played a season like that and had so many points," added Rangnick.
"At the start of the season, we just talked about being worry-free (from relegation) from the first match, therefore we're very happy."
Coach Ralph Hasenhuettl was emotional at the final whistle at Berlin's Olympic Stadium.
"I am simply proud," said the 49-year-old.
"There is no better place to celebrate direct qualification in front of so many fans. That was sensational," he added after around 10,000 RB fans made the one-hour trip to Berlin.
With 19 league goals to his credit, Leipzig's Werner, 21, is the highest-scoring German striker in the Bundesliga this season.
"Today the joy of reaching the Champions League dominates all else," said Werner.
"We have earned this over the year and have achieved something great.
"This was our little 'cup final', next year we will be amongst the best teams in Europe."
Werner made his Germany debut in March's 1-0 friendly win over England.
He will discover on May 17 whether he is part of die Mannschaft's squad for June's Confederations Cup in Russia from June 17-July 2 or will join Germany's Under-21 team at June's junior European championships in Poland.
"It's the next goal I have," he said.
"If I go to the Under-21s, then I will also be pleased.
"There is also something to be won there, but of course if I go to the Confed Cup then I will of course be absolutely delighted."