And, he had the gift to be able to pass his musical and dramatic insights to his musicians and cast. For all the passion and thrilling excitement he brought to his performances, he never overwhelmed his singers. The final scene from this classic Tosca illustrates all this, plus his mastery of tempi in the build up to the grand finale.

southerndoc1 agrees:

Tebaldi and other singers loved him, even if he did let the orchestra get too loud. He left us a wonderfully human Wozzeck and my favorite Don Giovanni from Salzburg, but it’s his Met Tosca that’s such a great example of live opera conducting. He knew he had three Rolls-Royce voices in super form, and he sensed just when to let them out , and when to rein them in. He and Renata give us the slowest, lushest ‘Vissi d’arte’ ever.

https://www.youtube.com/watch?v=F7u77WFkcKQ