Why did Karna get defeated by Gandharvas while Arjuna defeated them quite easily?

Why did Karna get defeated by Gandharvas while Arjuna defeated them quite easily? Karna got defeated because he got overpowered by the sheer number of the Gandharvas and was incapable of countering their Maya. Arjuna on the otherhand had trained for 5 years in Swarga and had became skilled in countering even the Maya of Nivatakavachas which was coveted by the likes of Ravana. Fighting Nivatakavachas and Kalakeyas, Arjuna was also experienced in fighting against giant armies single handedly. Karna says about his defeat While you looked on, I was worsted by all those gandharvas. My own army was routed and I was incapable of ensuring that they remained there. I was sorely wounded by the arrows and hard-pressed. I ran away. O descendant of the Bharata lineage! I think it is extraordinary that I see you here, without harm and without injury, and with all your wives, riches and vehicles. 533 (236), Ghosha Yatra Parva, Mahabharata. Karna admitted to being defeated by Gandharvas. He admitted that his army got routed. Karna admitted that he was severly wounded ( proving that the Kavacha Kundala doesn't protect anyone from wounds). He admitted that he ran away. Karna doesn't make any excuses like he was drunk to justify his flight. If that was a reason for his defeat, Karna would have surely mentioned it. Arjuna was an expert in countering Maya. He countered the Maya of Nivatakavachas which was so powerful that Ravana stayed with them to learn it Arjuna said, “Invisible, the daityas fought me with maya. With the power of invisible weapons, I continued to fight with them. The shafted arrows from Gandiva, empowered with mantras, sliced off their heads, wherever they were. At that, thus killed by me in battle, the nivatakavachas suddenly withdrew their maya and retreated into their city again. The daityas having fled and everything visible again, I saw the dead danavas there, in hundreds and thousands. There were shattered weapons and ornaments. 466 (169), Yaksha Yuddha parva, Mahabharata. Reference to Ravana learning Maya from Niivatakavachas Then again, lord, you waged war for a year against those powerful and indestructible danava heroes, with their powerful boons, and relying solely on your own might, brought them under your sway, tamer of your foes. And there you also acquired many powers of illusion, lord of the Rakshasas. 6 (7), Yuddha kanda, Valmiki Ramayana. So Arjuna was capable to countering the Maya of Nivatakavachas which was covered by Rakshasas like Ravana. So what match was Gandharva Maya against him ? Gandharvas tried attacking Arjuna the same way they did against Karna. But Arjuna repulsed them. Just as the gandharvas had shattered the chariots of Karna and the sons of Dhritarashtra into a hundred pieces, they attempted to do it again. O king! Hundreds of gandharvas attacked them in that battle and the tigers among men repulsed them with many showers of arrows. Repulsed by showers of arrows in all the directions, those travellers of the sky could not approach near the sons of Pandu. On seeing that the gandharvas were angered, Arjuna used great and celestial weapons against them. In that war, insolent about his strength, Arjuna used his agneya weapon to send a million gandharvas to Yama’s abode. O king! With his sharp arrows, Bhima, the great archer and supreme among strong ones in battle, killed hundreds of gandharvas. O king! Insolent of their strength, Madri’s two sons fought and captured and killed hundreds of enemies. When the gandharvas were thus killed by the great-souled ones with celestial weapons, they took to the sky and took the sons of Dhritarashtra with them. But Kunti’s son, Dhananjaya, saw them arise. He surrounded them on all sides with a great net of arrows. Having been tied down by that net of arrows, they were like birds in a cage. They angrily hurled showers of maces, spears and swords at Arjuna. But Dhananjaya pierced the bodies of the gandharvas with bhallas. Heads, legs and arms fell down from above like a shower of rocks and the others took fright. When the gandharvas were being killed by the great-souled Pandava, who was on the ground, they showered down arrows on him from the sky. But Savyasachi, the energetic scorcher of enemies, repulsed all of them with his own weapons and began to pierce the gandharvas. Arjuna, the descendent of the Kuru lineage, unleashed his weapons—sthunakarna,
indrajala,
soura, agneya and soumya. The gandharvas were burnt up by the arrows of Kunti’s son. They were in supreme despondence, like the daityas at Shakra’s hands. When they tried to escape upwards, his net of arrows restrained them. When they tried to slither away, Savyasachi restrained them with his bhallas. 531 (234), Ghosha Yatra Parva, Mahabharata. It's clearly stated that the Gandharvas attacked Arjuna the same way they did against Karna and Kauravas but got repulsed by Arjuna. Now Chitrasena personally was a friend of Arjuna. Arjuna learned dance and music from him during his stay in Swarga When Partha became skilled in the use of all weapons and the right time had come, Shakra told him, "O Kounteya! Now learn singing and dancing from Chitrasena. Learn the music that is only known to the gods and is unknown in the world of men. O Kounteya! If you learn this, it will bring your own welfare." Purandara then gave him to Chitrasena as a friend. Partha lived happily with him, free from all disease. 342 (45), Indralokabhigamana parva, Mahabharata. So it's likely that Chitrasena himself wasn't fighting Arjuna with his full power. But that doesn't mean that Chitrasena could have defeated Arjuna. Arjuna had already defeated the Gandharvas on 3 seperate occassions. In Adi parva, the strongest Gandharva, named Chitraratha was easily defeated by Arjuna with a single Agneyastra Having said this, the angry Pandava unleashed the blazing agneya weapon at the gandharva and it instantly burnt down his chariot. Knocked unconscious from the energy of the missile, the immensely powerful gandharva fell face down, dislodged from his chariot. Dhananjaya seized him by the hair on his head, which was adorned with garlands, and dragged the one knocked unconscious from the missile towards his brothers. 158, Chaitraratha parva, Mahabharata. During Khandava Daha, Gandharvas allying with other beings attacked Arjuna and Krishna but were crushed At that, the gods, the gandharvas, the yakshas, the rakshasas and the serpents rose up, uttering loud roars and desiring to fight. They were armed with iron clubs, chakras and bhushundis, with lightning in them. They were intent on killing Krishna and Partha, their great energy benumbed by their anger. Though they unleashed a fearful shower of weapons, Bibhatsu churned their upper limbs with his sharp arrows. The immensely energetic Krishna, destroyer of enemies, then wrought a great slaughter of daityas and danavas with his chakra. Pierced by arrows and struck with the force of the chakra, many powerful ones were pacified, like waves that reach a shore. 218, Khandava Daha parva, Mahabharata. Similarly, when Arjuna went on Digvijaya, he subduded all the Gandharvas in the north and extracted tribute On reaching Manasa, the lord Pandava conquered the regions around Hataka, protected by the gandharvas. As tribute, he obtained from the city of the gandharvas supreme horses that were the colour of partridges and speckled, with eyes like those of frogs. 250 (25), Digvijaya parva, Mahabharata. So even if anyone make the excuse that Chitrasena was fighting mildly, we have considerable proof that Arjuna was more than capable of defeating Gandharvas who were fighting seriously against him. Serious or mild, the Gandharvas were never any threat to Arjuna. Karna also seemed to improved his skills as later on he took on the Maya of Ghatotkacha on 14th night.