Why did Karna not try to save Jayadratha from Arjuna?

Why did Karna not try to save Jayadratha from Arjuna? He could not though he tried. He was first defeated by Bhima (while also failing to save a bunch of Duryodhana’s brothers who were fighting alongside him). He than broke yuddha-dharma by hiding behind his chariot and launching a sneak attack on Bhima injuring him temporarily. He was then defeated by Arjuna’s student Satyaki before he could even get near Arjuna. In fact Arjuna killed his son on that day enroute to Jayadhrata and Karna could not even defend his own son.