Maybe he was too inexperienced in the first fight and don't know how to phased himself that's why he run out of gas. He is also throwing uppercuts with the Jones fight but he was not hitting squarely because Jones keeps moving as opposed to Glover just standing with no head movements. That's why his uppercut is very evident on that fight. I remember he hits Glover 3 or 4 successively, Teixeira is a stationary target.
Here are highlights from Gustafsson's fight with Glover Teixeira.
https://www.youtube.com/watch?v=fWVdOq_5zZsGustafsson's punches seem to land with more impact and force than they did earlier in his career when he fought Jon Jones. You can actually see Glover Teixeira's head snap back from the force of the punches, which mostly glanced off Jon Jones head as they lacked the same type of commitment or body weight behind them.
I re-watched the 1st fight between Jones and Gustaf from the link tokeweed posted above. The kicks to the body Jones landed and the spinning elbows could be what caused Gustafsson to tire.
Those are the impressions I get. Feel free to agree/disagree.
@Kemrait. What is phased?
@Hydrogen. Jon Jones also has improved his boxing. I reckon the biggest difference between his fights from before and the fight next week will be his hands. They will be faster, stronger and they will hit their targets.
My prediction is a doctor's stoppage on the 5th round because Alexander Gustaffson's eyes are closed shut courtesy of Jon Jones' boxing hehehe.
I think Kemarit meant to type "pace himself" instead of "phased himself".
Don't know if Jones has improved his boxing. He does most of his damage with kicks and spinning elbows. He's never inflicted serious damage with punches in a fight that I know of.