This segment of yesterday's sprint race is exactly what I mean (3:19):
https://youtu.be/yd6wp8p8Bws?t=199
Ricciardo has just passed Alonso, but the latter is not giving up without a fight. Exiting Luffield Alonso is on the outside but quite a bit back. However Ricciardo is still leaving him racing room on the track and doesn't let his car drift wide onto the kerb.
That's mutual respect and provides the trust to go side by side in the most tense situations. No one would've thought anything of it if he had let his car run wide, but still he makes sure he leaves Alonso room just to be sure and we had a nice battle continuing for half a lap.