The Biancoceleste followed last weekend's 3-0 win at Cagliari with a 1-0 triumph over FC Zurich in the Europa League on Thursday.
Christian Brocchi's goal handed his team their first success in Group D and lifted the Romans to second in the standings.
"I am pleased with the outcome but I know there is still a lot of work to do for us to qualify for the next round," Reja said.
"The important thing is that we are giving continuity to our results and that the team is growing game by game."
Lazio, who are level on 18 points with second-placed Udinese in Serie A, have not lost at home since September 18.
Moreover, they will fancy their chances of claiming maximum points on Sunday with Parma having won just once on the road this season.
The Ducale club head into the encounter in the Italian capital eager to pick up where they left off in their 2-0 triumph over Cesena last time out.
The result allowed Parma to bounce back from defeats to Atalanta and AC Milan, and saw them climb five points clear of the relegation zone.
Parma coach Franco Colomba knows his side will have to show the same fighting spirit if they are to surprise in-form Lazio tomorrow.
"Lazio deserves maximum respect," Colomba said. "They are third in the standings and have improved a lot with respect to last season.
"We will have to be focused from start to finish if we are to have a chance of beating them."