Standing in for sickened Emanuel Ax in February 2005, Siirala gave a sensational debut recital at the Cologne Philharmonie. According to the newspaper Kölner Stadt-Anzeiger “His recital will be remembered as one of the most outstanding events of this season”. Stepping in for indisposed famous colleagues seemed to be his brand mark throughout the season 2006/07: whether replacing Hélène Grimaud for concerts with the SWR-Sinfonieorchester Freiburg/Baden-Baden under Gielen with his musically expressive but symphonic interpretation of Brahms’ 2nd piano concerto, or Ivo Pogorelich at the Schumannfest Düsseldorf, Michail Pletnev at the Maggio Musicale or Yefim Bronfman with the Bamberg Symphony under Blomstedt, playing Brahms’ 1st piano concerto: everywhere press and audience were enthusiastic about his playing. Blomstedt even invited him to join him at the Baltic Sea Festival the same season and the Bamberg Symphony re-invited him to come back for four concerts with his compatriot Pietari Inkinen in November 2007.
