Why is Kripacharya known as 'Samitinjaya'

Question

In the Shrimad Bhagwad Geeta, Chapter 1, when Duryodhana describes his warheads to Dronacharya, he uses everybody's name but he refers to Kripacharya as 'Samitinjaya'. Why does he use Samitinjaya (it means sangramvijayi, 'the victorious in war'), when Bhishma Pitamahaa is also undefeated and why does he use that word specifically for Kripacharya, and no alankars for other warheads?

भवान् भीष्मश् च कर्णश् च कृपश् च समितिञ्जयः

अश्वत्थामा विकर्णश् च स्औमदत्तिस् तथ्ऐव च १.८

bhavān bhīṣmaś ca karṇaś ca kṛpaś ca samitiñjayaḥ

aśvatthāmā vikarṇaś ca saumadattis tathaiva ca 1.8

Reference: 1, 2

Answer 1

The word samitiñjayaḥ is being applied to Bhishma as well.. Here is what Prabhupada's commentary on this verse says:

Duryodhana mentions the exceptional heroes in the battle, all of whom are ever victorious.

And here is what Sridhara Swami, an Acharya who belonged to the Rudra Sampradaya of Vaishnavism, says in his commentary:

Samjitinjayah means always victorious in battle. This applies to Drona and Bhishmadeva and all the warriors named herein. The son of Somadatta was known as Bhurishravas.

And here is what Keshava Kashmiri, an Acharya who belonged to the Kumara Sampradaya of Vaishnavisn, says in his commentary:

The adjective samitinjaya meaning always victorious in battle applies to these four being Drona, Bhisma, Karna and Krpa. Then he points out others who are almost as powerful as these four such as Asvatthana and others. Asvatthama is the son of Drona.

So Kripacharya isn't being singled out as unique.