Vokes replaced Craig Bellamy at half-time in Wednesday's 2-1 friendly victory over Austria in Swansea, and took little time to make an impact as he emphatically headed home the Dragons' second goal from Gareth Bale's pin-point cross.
The strike made Vokes the first Wales player other than Bale to score during Chris Coleman's time in charge, and the 23-year-old also linked up play well and proved a useful outlet when the home side came under pressure during the latter stages.
Coleman opted to go with a front three of Bale, Bellamy and Jack Collison at the Liberty Stadium, but the former Fulham boss, like Gary Speed before him, has used Steve Morison as his preferred centre-forward option.
But Vokes, who like his rival has been short of starting opportunities at Burnley this season, is doing all he can to usurp the new Leeds signing.
He said: "It was great to come off the bench and get a goal, you always have a point to prove when you come on as a substitute and that is what I hope I did.
"Gareth did really well on the wing and put a great ball in. You have to take every chance you can get at this level to show your worth and I feel I did that.
"Hopefully this proves a point and I can push for a starting place for club and country.
"Everyone wants to play and we have two important games next month, so I hope scoring will help my cause."
The win gives Wales some valuable momentum before facing Scotland at Hampden Park and Croatia back at the Liberty Stadium, and Vokes believes the performance against the Austrians shows what they are capable of with their star names available.
"Games in international football are always so far apart but we can try and use this performance as a confidence boost going forward," he said.
"It is always important to show you have a strong squad and how much the lads want to play, we showed how good we can be."