regardless of who was favored, i'm pretty sure down 1-4 in the 3rd would be considered "in doubt"
For you maybe. It was only 1 break of serve Tsonga was down.
Some players have histories of not closing out matches and sets. Wawrinka was up 2 breaks of serve in the 2nd set against Nadal in the Stuttgart final and was it surprising Nadal won the match in 2 sets. The answer is no, therefore never in doubt.