Complex sentence: Sastre, for his part, was quiet, finishing in the top ten of a stage only once, in Stage 15, and never threatening the race lead, finishing 17th overall, more than 26 minutes behind Contador as Tour champion.
Split into simpler sentences: Sastre, for his part, was quiet, finishing in the top ten of a stage only once, in Stage 15. Sastre never threatened the race lead, finishing 17th overall, more than 26 minutes behind Contador as Tour champion.