"She's grown in confidence being in the environment, and she's really loving playing at goal shoot, and I think that is huge for her," the Ferns coach said.
Mes, who cemented her place in the Silver Ferns shooting circle only last season, is still coming to terms with her senior status in the group.
"It is a little bit strange, it is a really great opportunity. I feel like I've been here a while, but when I look at it it's probably not actually that long."
Rather than celebrating her individual performance in the weekend's season opener, Mes was more pleased with the way the attack end came together following a limited build-up.
For an all new attacking line-up there were very few miscommunications between Laura Langman, Shannon Francois, who was a late inclusion in the starting line-up in place of Grace Rasmussen, Ekenasio and Mes, with the Ferns playing with confidence and speed.
"We had had a little bit of time together, but not much. So it was a case of staying connected and keeping the talk up. I felt like we moved the ball around well and we mixed it up a lot," said Mes.
There could be more changes to come in Wednesday's second Quad Series test against South Africa, with the match-up against the world number fives presenting an opportunity for Southby to blood some of the newcomers to the side.
Replacement defender Jane Watson and shooter Te Paea Selby-Rickit could be in line for further court time after making their test debuts against England, while 19-year-old shooter Maia Wilson may get the chance to notch up her first cap.
But Southby said with the a key match-up looming against world champions Australia this weekend, it is important that the team first consolidate their starting line-up.
"We'll look at that and see if the opportunity is there to do that, but first and foremost it's about making sure our connections are growing and that we settle," said Southby.
"There were a couple of unsettled patches [in the opening test] and I think it's just making sure when people come on they are able to settle into it, because when you're playing against an opposition that is nailing everything you can't afford to have those lapses."
Netball Quad Series
Wednesday: 7.45pm Silver Ferns v South Africa, Claudelands Arena, Hamilton; 9.30pm Australia v England, Adelaide Entertainment Centre, Adelaide.
Sunday: 3.30pm England v South Africa; 5.30pm Australia v Silver Ferns - both Margaret Court Arena, Melbourne.
