Rock Saccone ahead of Tuesday's special congressional election, then pivoted to his own re-election message.
"You'd be so bored", Trump said as he brushed off criticism that he should change his ways.
"Do you think the drug dealers who kill thousands of people during their lifetime, do you think they care who's on a blue-ribbon committee?"
Trump said he heard the 33-year-old Lamb was "nice-looking" but said: "I think I'm better-looking than him. I do. I do. I do".
Trump faced multiple accusations of sexual assault by women during the 2016 election, after the notorious Access Hollywood tape surfaced on which he boasted of groping women. Bernie Sanders, Massachusetts Sen. Elizabeth Warren, D-Mass. - again pulling out his "Pocahontas" taunt.
"Our new slogan, when we start running, in - can you believe it, two years from now - is going to be, Keep America Great, exclamation point", the President said.
Trump also said he wanted to take on Oprah Winfrey in the 2020 presidential election.
"Oh I'd love Oprah to win, I'd love to beat Oprah".
"We're saving the steel, and a lot of steel mills are now opening up because of what I did", Trump said.
Death penalty for drug dealers? Count Trump in
"You think her life is so easy folks?" "Should we be following China's lead when it comes to criminal justice?"
"Who knows what's going to happen?" Trump said Lamb will still back the Democratic agenda in Congress. "I don't know if this country's ready for it".
Trump's appearance was aimed at helping Republican Rick Saccone in a district Trump won overwhelmingly in 2016 as part of a narrow win in Pennsylvania. The election is set for Tuesday.
"The people of Pittsburgh can not be conned by this guy Lamb", Trump said, dismissing Lamb's efforts to run as a moderate Democrat.
President Donald Trump told western Pennsylvania voters Saturday night that his new tariffs were saving the steel industry and urged them to send a Republican to the House so he can keep delivering those kinds of results.
It recalled the President's message during an White House summit on opioid abuse at the beginning of the month.
Trump also touted his new tariffs on steel and aluminum, which are popular in the district in the heart of steel country. Just days before the Alabama special election, Trump held a rally on the Alabama-Florida border, where he endorsed Moore, but once again made a speech largely about himself.
And on the topic of worldwide trade, Trump faulted his predecessors all the way back to President Ronald Reagan, who held office for most of the 1980s, for what he sees as the current unfairness in the country's trade relations with much of the rest of the world.
And, this week, the porn star known as Stormy Daniels sued Trump in a California court, claiming Trump never signed a hush agreement regarding an alleged sexual encounter between the two, therefore rendering the agreement void.