We see his quick learning ability as he was instantly able to use Kamehameha against Master Roshi. He eventually wins the tournament defeating Kid Goku in the finale. It was also the arc when he made his face turn.
While the King Piccolo saga started with the death of Krillin, Tien played a major role throughout the arc and even confronted King Piccolo with Evil Contamination Wave also known as Mafuba to some.
On the last arc of Dragon Ball, Tien lost to Goku in 23rd World Martial Arts Tournament, but it remained very clear that Tien was leagues above Krillin. He was more powerful and was also naturally more talented with a set of bizarre attacks and techniques like sprouting extra arms, splitting into four bodies, being able to use three eyes to detect his opponents better, and more
On the part of Dragon Ball, it is 100% clear without an ounce of doubt that Tien was superior to Krillin from every angle up to that point, but things started changing after the start of Dragon Ball Z. We are now waiting for the Tournament of Power in Dragon Ball Super, but till this point, they managed to make it very vague about who is the stronger one. You see some stuff and think Tien is stronger, and then you can find statements from very authentic sources that would say otherwise. Anyways, for now, let’s stick to the anime and get to the bottom of it.
So, Dragon Ball Z first Saga, Krillin undoubtedly had more contribution in the battle against Vegeta and Nappa. He would be among the top regarding being resourceful in Saiyan Saga. He bought a lot of time before the arrival of Goku and survived to the very end. On the other hand, Tien got killed by Nappa after he decided to give everything he had in his attempt to take down Nappa out of a sheer desire for revenge of Chiatzuo’s death. However, even though Krillin was more resourceful in the battle, it doesn’t necessarily indicate that he was stronger than Tien. Instead, he was very strategical managing to survive longer. Besides, at the end of Dragon Ball Tien was still quite stronger than Krillin, and Krillin didn’t perform any feat in this saga that would put him above Tien. Anyways, if there were some kind of point considering the arc only, I would call it a draw.
In Dragon Ball Universe who is more powerful Krillin or Tien? Taking in consideration- Dragon Ball, Dragon Ball Z ( Buu arc) to Dragon Ball Super ( Episode 80). Check out the full video for my thoughts!