Southgate was happy with Lingard's "outstanding" performance against Malta, but suggested that there was still a chance Rashford could start in Slovenia.
"I've got to look at how Slovenia played and see what's better suited for the game. I think in terms of the decisions we made, Jesse Lingard came in and was outstanding," he told reporters.
"He linked the play really well and showed really good creativity at times. His links with Dele [Alli] and Danny [Rose] on that side of the pitch were really, really exciting. Of course we've had three-and-a-bit days working with the players, so I've got to be realistic about how quickly some of the ideas can take place.
"In moments we moved the ball really well. I think at times we moved it a bit too slowly in the second half, and at times we played a bit longer than we needed to. But all those things will come in time."
Daniel Sturridge and Alli got the goals for England in their 2-0 win.