"It's always a battle. You have to impose yourself in all areas and to be the best in everything to beat Real Madrid," Iniesta said.
In La Liga Messi has 250 goals, one short of the scoring record of Telmo Zarra for Athletic Bilbao.
Goals from Neymar and Lionel Messi helped Barcelona to a 3-1 victory over Ajax as the Spanish giants recovered to winning ways in Europe.
Paris St Germain lead Group F with four points followed by Barca on three points and Ajax on two.
Suarez signed for Barca from Liverpool for 81 million euros despite the ban for biting Giorgio Chiellini when playing against Italy in Brazil.
Messi has a chance against Real Madrid to beat Telmo Zarra's record of 251 goals for Athletic Bilbao in the 1940s and '50s.
Messi edged one closer to La Liga's all-time goalscoring record as Barcelona easily beat Eibar 3-0 at Camp Nou on Saturday.
Lionel Messi will have another chance to match or surpass Telmo Zarra's six-decade-old La Liga scoring record of 251 goals when Barcelona host promoted Eibar.
Suarez is looking a lot sharper since he returned to training and will be ready for his debut in the Clasico against Real Madrid, says coach.
Messi needs just two goals to equal Telmo Zarra's all-time Spanish top-flight record of 251, set in the 1950s.
Barcelona forward Luis Suarez is looking forward to ending his FIFA ban and says he will be fit to face Real Madrid if selected later this month.