 Complete the following phrase:  Díaz was an improved runner at the start of 2015 and set personal bests in the 1500 metres 3:40.15 and 3000 metres 7:56.34. He set a new best in the 10K run, defending his title in that section of the Santiago Marathon with a time of 28:45 minutes. At the age of twenty-one, Díaz established himself as one of the regions top middle-distance runners at the 