The Welsh flanker is breathing down Tom Croft's neck in the race for a starting berth in the Test side but the outgoing Newport Gwent Dragon was in first-team action against the Rebels.
And alongside his compatriot Toby Faletau and Ireland's Sean O'Brien in the back-row they all impressed in the five-try romp.
Conor Murray, Sean Maitland, O'Brien and Ben Youngs all went over for the visitors at Aami Park while the forwards earned a late penalty try as well.
And Lydiate, who only returned from a broken ankle at the end of the RaboDirect PRO12 season, could not hide his delight after taking over the captaincy when Geoff Parling was withdrawn from the side in preparation for the second Test.
"It's the pinnacle of my career to captain the Lions, it's a massive honour and to get the result tonight as well makes it even better," he said.
"We had to up our game coming here. We wanted to get a result and keep our momentum into the weekend because it's a massive game on Saturday.
"It's always going to be tough after the Brumbies game but getting the result on Saturday really helped.
"A lot of boys missed out for the weekend and they were so keen to take their chance."
Lydiate, Faletau and O'Brien all put themselves forward for selection against the Rebels while Manu Tuilagi and Maitland impressed in the back-line.
And Lydiate admitted afterwards that a number of players had given Warren Gatland something of a selection head-ache before Saturday.
"We wanted to play well as a team and as an individual to try and push yourself forward for Test match selection, credit to the Rebels because they certainly gave us a good game," he added.
"And a few of the boys are definitely putting their hands up for selection this week."
