The Danish badminton star is on his way back to his usual level, after he has largely not played badminton for the past six months.
Back in April, Axelsen underwent surgery for a back injury, and only a month ago did he make a comeback at a tournament in Hong Kong.
Axelsen had a poor start to the quarter-final and was behind 0-4, but the Dane gradually clawed his way back into the set in a high-paced match.
However, when Axelsen seemed to have things under control, Vitidsarn geared up and won ten successive points to claim the first set.
Axelsen came back roaring in the second set. The two-time Olympic champion was ahead 11-4 and never looked back as Vitidsarn was given no chances to get back into the set.
Vitidsarn showed superb badminton in the third set and numerous times caught Axelsen off balance. But the Dane often ended up winning points when he otherwise looked to be outplayed.
Both players seemed exhausted at the end, but thanks to enormous backing from the passionate crowd in Odense, Axelsen found the strength to book his way to the semi-final.