Shalya said O Karna, this (Arjuna) the best of warriors even when alone, is considered to be unconquerable by all the warriors and now when he is protected by Krishna it is really a venture to try to face and defeat him.
शल्य उवाच अजय्यमेनं प्रवदन्तिन युद्धे महारथाः कर्ण रथप्रवीरम्। एकाकिनं किमु कृष्णाभिगुप्तं विजेतुमेनं क इहोत्सहेत॥