Well, from what I've been able to glean from sources, this seems to have been regarded as a minor battle (at best) at the time. While it was a clear victory for the Abbasid ghazi and their allies there doesn't seem to be much to be drawn from it militarily.
The Korean commander of the Chinese forces - Gao Xianzhi - severely underestimated the Abbasid numbers of troops. He thought that he had a superior number and marched to the attack when in reality he had parity or even a small inferiority. The Chinese cavalry were able to push back and severely press their Muslim counterparts, but an Abbasid detachment was able to ford the river the battle was named after and flank the Chinese infantry. As they began to roll the line, the Karluk mercenaries (who formed a majority of the Chinese forces) defected and effectively cut the infantry off from the rest of the army. The infantry was slaughtered but they were mostly allies and recruits from the area. Gao was able to withdraw most of the Chinese troops, but their allies suffered heavily. The Chinese were not trusted by peoples in central asia again (in very broad terms).
I would say that this battle illustrates the weakness of China in dealing with foreign ethnic groups. The T'ang period that this battle was in is one of the high points of Chinese expansion and foreign policy periods...yet they lost influence on central asia due to incompetence.
Gao's retreat under combat conditions and preservation of his core forces shows a good deal of discipline, especially with how quickly he was able to get his forces back up to strength afterwards. A plus in China's military column.
Even without the desertion of the Karluks, the Abbasids were working on flanking and rolling the Chinese line. It is possible that they would have won just as much of a victory on their own. This shows the relative strength of using the ghazi system when expanding control over new areas. At least in my opinion. The ghazis had a vested intrest in converting, signing on to Muslim armies and winning new areas of influence. They would have their names on the military rolls for loot (though not as high as earlier troops-hence a problem that eventually broke the Ghazis) and proably end up as tax collectors and timur land holders. Also if you signed on and had lands already under your control, you could retain local control of them instead of losing them to the Caliphate.
So mostly I'd say this battle shows the strength and weaknesses of the respective governmental policies at the time rather than military differences.
Now with the prisoners taken by the Abbasids and the effects on society (like paper making technology coming to Baghdad) illustrates how the Caliphate definitely won more than China.