The Three Lions now have an 11-day break before they take on Tunisia in their World Cup opener and Rashford's performance poses a healthy dillema for Southgate.
Looking ahead at England's first two World Cup matches against Tunisia and Panama, Gareth Southgate and his players should be very confident.
Neither he nor Vardy, the Leicester City striker, featured in Saturday's 2-1 victory overNigeria at Wembley. "That is epitomised by the three lads that have been with us on standby with their outstanding professional attitude".
Rashford, who impressed throughout with his speed and control, fired England ahead in the 13th minute, unleashing a dipping diagonal drive from the right which flew past helpless Costa Rica keeper Keylor Navas.
It was left to Danny Welbeck, who came off the bench to put the game to bed with a diving header past an on-rushing Navas following a cross-field delivery from Dele Alli. Tournament football is a different environment to a friendly worldwide, but this performance in this was a huge positive ahead of the World Cup.
Jack Butland starts in goal with Ruben Loftus-Cheek also earning a starting berth against their fellow World Cup finalists.
That opens up several opportunities but the simplest could be the best and I'll play England to win to nil at [2.08].
After the game, Rashford said he believed "anything's possible" when discussing England's chances of winning the tournament.
The two-hour documentary, "When Greed and Corruption Become the Norm", was provided to the authorities last month before being screened in public for the first time on Wednesday.
England return to the Broad Acres for the first time since March, 2002 when they host Costa Rica at Elland Road tomorrow night in front of a sell-out crowd. We are not just a London-based team.
How big of a chance to England have to win the world cup?
Rashford (centre) was too good.
If we're not expecting Costa Rica to contribute, the [1.96] for Under 2.5 goals could be the way to go.