The president declared victory in a brief tweet: "5 for 5!"
Trump in a second tweet accused the media of downplaying the Republican Party's record of success in special elections.
"The Republicans have now won 8 out of 9 House Seats, yet if you listen to the Fake News Media you would think we are being clobbered. Why can't they play it straight, so unfair to the Republican Party and in particular, your favorite President!" he wrote.
The president left out a special election in Southern California to replace former Rep. Xavier Becerra (D) in which no major Republican candidate ran.
Trump also claimed that "as long as I campaign and/or support Senate and House candidates (within reason), they will win!" and said Republicans will "have a giant Red Wave" in November's midterms "if I find the time" to hit the campaign trail.