Walker picked up an overhit corner on the right flank and subsequently delivered a pinpoint deep cross of his own, picking out Rashford who controlled a cushioned volley past Sommer from close range to score in back-to-back England games for the first time.
"We were trying to correct one or two things but also challenge them a bit, it was an important night for us to finish well and we knew it would be hard because of the changes and amount of game time, but I'm really pleased because the players have given everything this week".
"We know the performance could have been better".
The two teams could have met in the quarter-finals in Russian Federation had the Swiss not limped out of the competition with a whimper to Sweden in the last 16.
Shaw superbly set up Marcus Rashford's opener on his first England start since September 2015 - an appearance that came just a week before he suffered a double leg-break in a Champions League tie.
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Switzerland were soon gifted a chance to settle into the game, though, as Jack Butland's attempts to play out from the back nearly backfired twice in quick succession - the second of which saw James Tarkowski robbed of the ball and Xherdan Shaqiri subsequently fire a low strike against the outside of the post when he should have done better.
"We could see how good a side Spain were at the weekend".
A more positive start to the second period for the hosts was rewarded with the only goal on 54 minutes when Kyle Walker's hanging cross to the back post was swept home by Rashford for his fifth worldwide goal.
"To get two goals this week, two really good finishes, is really important for him".