The left-back's cross led to the only goal of Scotland's European Championship qualifier against Georgia at Ibrox - visiting goalkeeper Giorgi Loria could only palm the ball to Shaun Maloney, whose shot eventually went in off defender Akaki Khubutia.
Fletcher got on the end of another two deliveries from the Hull player, heading one over from a tight angle and being foiled by Loria and an offside flag from a low delivery.
The 20-year-old sent over a number of other crosses that had pace, accuracy and movement and caused problems for the visitors.
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Robertson was making his competitive debut for Scotland and winning only his third cap but had the confidence to bomb forward at every opportunity.
And Fletcher feels the former Queen's Park and Dundee United player will provide himself and other Scotland strikers with plenty of ammunition in the years ahead.
The Sunderland striker said: "He's got a great delivery, you see that week in week out when he's playing for Hull.
"I think if we can keep him fit and playing for Scotland then we will create a lot of chances and score a few goals."
Robertson was not the only source of opportunities for Gordon Strachan's side with Fletcher helping set up some of the opportunities that fell for Steven Naismith, whose final product fell short of his usual standards.
But Fletcher enjoyed his partnership with the Everton player, who played just off him through the middle.
The 27-year-old said: "We've been working together from a young age in the under-21s. We have done it before and have done it in training. So it's not something strange. It's been good.
"We're happy with the performance. We created a lot of chances. If we weren't creating chances we would start questioning ourselves.
"But we are creating a lot of chances. On another day a few more would have gone in. If we had got the second goal it would have been a lot more comfortable but we stuck in and got the three points.
"We created a lot of chances and hopefully on Tuesday we can take a few of them."
Scotland face Poland in Warsaw knowing that they risk falling six points behind their hosts, who stunned world champions Germany on Saturday night to win 2-0.
But Scott Brown scored the only goal when the teams met in the same venue in a March friendly and Scotland have also won in places such as Croatia, Norway and Macedonia under Strachan, as well as giving Germany a fright when Ikechi Anya scored in between a Thomas Muller double in Dortmund last month.
And Fletcher is going to the Polish capital full of belief that Scotland can take something.
"We have got a lot of pace with Kech, hopefully we can capitalise on that on Tuesday night," the former Hibernian player said.
"If we play like we did against Georgia then I think we have a great chance.
"We have played Poland away from home and it's going to be tough but we know what it's about, we know what the atmosphere will be like."
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