34 years old.  5 feet 9 inches.  World No. 358.  No career ATP finals.  One main-draw appearance in the last 12 months.  Long history of injuries.  None of those facts augured well for Bjorn Phau entering this week, but the qualifier from Germany has defied them all so far.  

Before arriving in Zagreb, Phau had played just one tournament at any level this year.  He failed to qualify in the main draw of a Challenger, a result that enhanced doubts over his ability to continue competing at the professional level.  Phau's famous knack for flinging himself around the court like a fireball of energy seemed to have caught up with him at last.  But six consecutive wins at the ATP 250 tournament in Croatia have shone a ray of hope upon his future.  Perhaps Phau still can eke out a few notable results in the twilight of his career.

Extended to three sets in the second round of qualifying, the German not only survived that test but defeated an in-form Daniel Evans to reach the main draw.  Evans, who upset Philipp Kohlschreiber in a Zagreb quarterfinal today, could meet Phau again on Sunday in the first ATP final for both men.  Just as astonishing as the Brit's run, however, is what Phau has accomplished in upsetting No. 2 seed Mikhail Youzhny and world No. 78 Dudi Sela to reach the semifinals.  He had won just 11 total matches in ATP main draws over the last three years and had not appeared in an ATP semifinal since 2009.  Especially impressive was his comeback against Youzhny in a match that Phau trailed by a set and a break.

Tomorrow, Phau seeks his first ATP final against home hope Marin Cilic, a match that few will expect to him.  Although he currently ranks lower than Youzhny, Cilic owes that diminished status in large part to a controversial suspension from which he returned last month.  Phau's height leaves him at a natural disadvantage in a battle against a towering Croat, who can strike serves at angles difficult for him to retrieve.  These indoor hard courts in Zagreb have witnessed some of Cilic's most impressive tennis before, moreover, including three of his nine career titles.

But,even if his fairytale run ends in the semifinals, Phau will have accumulated wins and ranking points invaluable for bolstering his comeback.  A week in which six players advanced from the qualifying draw to main-draw quarterfinals has showcased no underdog more improbable than the tireless German.