The network's highest-rating show on Monday, which is one of the biggest viewing nights of the week, was Ten News at Five coming in at 16th with an audience of 713,000.
Its marquee series MasterChef: The Professionals languished in 25th place with 443,000 viewers.
Chat-fest Can Of Worms was 29th with an audience of 398,000.
While The Project, which has been used as a ratings barricade against news and current affairs programs in the past, is starting to give.
On Monday it was 23rd with an average audience of 463,000.
McLennan was appointed as the replacement for chief executive James Warburton, whose contract was terminated last Friday.
But McLennan will not step into the role until on March 18 and he will have to hurriedly decide "where to now" for Ten after a string of failures, most of which were reality shows.
In contrast to Ten's ratings wows on Monday, the Seven Network's two biggest hits had more viewers than MasterChef, The Project and Can Of Worms combined.
My Kitchen Rules won the evening with 2.180 million viewers and Revenge pulled 1.360 million to be second.
The Nine Network had four Top 10 shows including Nine News (1.302 million), which was third.
The Block All Stars is now pulling million-plus audiences on a more regular basis and on Monday it was sixth with 1.194 million viewers.