Shelton finished off last year with a couple of impressive showings on the US ATP Challenger Circuit. He won back-to-back trophies and secured a Top 100 debut before the season concluded.
It was the perfect way to end that season, but very few people expected him to start next year in an even more impressive way. He played his maiden Grand Slam outside of the US at the Australian Open and immediately made it to the second week.
He impressed many with his level, and that started the legend of Shelton. He slowly improved over the year, hitting a new peak at the US Open with a run to the semi-final.
A recent trophy run at the Japan Open pushed him inside the Top 15, which is another thing nobody really expected. Ruud himself was quite surprised by the improvement from Shelton this year and how quickly his career progressed.
He really impresses me. He never gives up. He keeps fighting, keeps hustling, and I've seen it many times before - he has a great attitude. You kind of feel surprised how fast it's gone for him. But I'm not surprised at the same time. He's going to be dangerous for years to come and he is going to improve.
As long as he keeps the right attitude and keeps working hard, there's no limit [to what he can achieve]. I wish I had that arm [for his serve], it’s like 140-145mph. So it seems like a dream.
There are some shades of Nadal there, as Shelton grew up idolising the Spanish superstar. We'll see how his career goes but so far he's been really impressive across the board.