The Blue Jays are now 2-2 on their current six-game homestand after taking the opener of the three-game series.
Toronto starter Kevin Gausman (10-8) allowed three runs, seven hits and two walks in five innings. He had seven strikeouts and now has 202 on the season.
Washington starter Josiah Gray (7-11) allowed four runs, four hits and four walks in two innings.
The Nationals took a 1-0 lead in the first. Abrams led off with a single, stole second and scored on a single by Meneses.
Toronto scored four runs in the second. Jansen and Kevin Kiermaier walked. George Springer hit an RBI single, and Vladimir Guerrero Jr. extended his hitting streak to nine games with a two-run double. Davis Schneider added a run-scoring single.
Jansen hit his 16th homer of the season with one out in the third against Robert Garcia to make it 5-1.
Abrams led off the fifth with a single, and Lane Thomas was hit by a pitch. After a double steal, Meneses stroked a two-run double to right.
Jansen was walked by Andres Machado with two outs in the home fifth. Ernie Clement had an infield single and Kiermaier followed with an RBI single.
Trevor Richards replaced Gausman and was perfect in the sixth and seventh. Genesis Cabrera had a clean eighth for Toronto.
Jordan Hicks pitched around a walk in the ninth to earn his 12th save.
Toronto put third baseman Matt Chapman (right middle finger sprain) on the 10-day injured list on Monday and recalled Clement from Triple-A Buffalo.
Clement started at shortstop on Monday for Bo Bichette (quadriceps), who is listed as day-to-day.
—Field Level Media