The game was suspended due to rain after 10 innings with the score tied at 3 and will pick up on Tuesday at 5 p.m. ET.
"I felt good going into it," Giolito told MiLB.com after the game. "I knew that in the bullpen I had all my pitches working, so I was able to put together a good five innings despite being a little erratic with control. Hopefully we finish it off tomorrow."
Selected in the first round of the 2012 Draft, Giolito went 10-2 with a 2.20 ERA last year. The Nationals held him and No. 3 prospect Reynaldo Lopez out of the first month of this season after both reached their innings limits in 2014.
"I made a mechanical adjustment to keep my weight back and keep my mechanics more smooth," Giolito said to MiLB.com. "I've kind of brushed off some rust and I feel a lot better moving forward."
Alex M. Smith is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.