Henry of Transtamare had troops more numerous, but less disciplined and experienced.

The two armies joined battle on the 3d of April, 1367, at Najara or Navarette, not far from the Ebro.

Disorder and even sheer rout soon took place amongst that of Henry, who flung himself before the fugitives, shouting, "Why would ye thus desert and betray me, ye who have made me King of Castile?
Turn back and stand by me; and by the grace of God the day shall be ours." Du Guesclin and his men-at-arms maintained the fight with stubborn courage, but at last they were beaten, and either slain or taken.

To the last moment Du Guesclin, with his back against a wall, defended himself heroically against a host of assailants.
The Prince of Wales, coming up, cried out, "Gentle marshals of France, and you too, Bertrand, yield yourselves to me." "Why, yonder men are my foes," cried the king, Don Pedro; "it is they who took from me my kingdom, and on them I mean to take vengeance." Du Guesclin, darting forward, struck so rough a blow with his sword at Don Pedro, that he brought him fainting to the ground, and then turning to the Prince of Wales said, "Nathless I give up my sword to the most valiant prince on earth." The Prince of Wales took the sword, and charged the Captal of Buch with the prisoner's keeping.

"Aha! sir Bertrand," said the Captal to Du Guesclin, "you took me at the battle of Cocherel, and to-day I've got you." "Yes," replied Du Guesclin; "but at Cocherel I took you myself, and here you are only my keeper." The battle of Najara being over, and Don Pedro the Cruel restored to a throne which he was not to occupy for long, the Prince of Wales returned to Bordeaux with his army and his prisoner Du Guesclin, whom he treated courteously, at the same time that he kept him pretty strictly.