I cannot say I ever bother to benchmark parsing algorithms across languages in MS-DOS, so maybe that was a case where Turbo C might have won a couple of micro-benchmarks.
That was just an example. In general, properly written TP code (properly configured) was on par with properly written TC code, and both were slower than properly written Watcom code in my experience - I did them all and switched frequently.
Parsing was one example where C shone above Pascal, and there were others. My experience was Watcom was consistently better, but in general C was sometimes easier/faster, Pascal was rarely easier/faster, and if speed mattered ASM was the only way.
Well, as I mentioned in several comments, in what concerns my part of the world, in a time and age where a BBS was the best we could get for going online, Watcom did not even exist on my radar until MS-DOS 32bit extenders were relevant.
So we are forgetting here the complete 8 bit generation, and 3/4 of MS-DOS lifetime.
Parsing was one example where C shone above Pascal, and there were others. My experience was Watcom was consistently better, but in general C was sometimes easier/faster, Pascal was rarely easier/faster, and if speed mattered ASM was the only way.