Fletcher was a late substitute as Cherries' 15-match unbeaten run in League One bit the dust following a 3-1 defeat at the Banks's Stadium on Saturday.
Eddie Howe's men, who had seemed invincible until their colours were lowered by the Saddlers, will be hoping to get back on track when they face bottom-placed Hartlepool tomorrow night (7.45pm).
Hartlepudlian Fletcher said: “We weren't at our best by a long shot against Walsall but, as disappointing as it was, we have got to look back and say we have done fantastically well.
“We need to use it as a timely reminder because we aren't just going to walk up the league and walk into the promotion spots.
“As much as we can beat teams, we can be beaten ourselves. As well as Walsall played, we still had chances.
“We have got to start again and kick on. We have got to remember what defeat tastes like and make sure we don't repeat it. We have got to go to Hartlepool and make sure it doesn't happen again.
“We will need to be on our mettle because Hartlepool is not an easy place to go. It doesn't matter where you are in the league because anybody can beat anybody.
“If we aren't on our game, we will be turned over. From the first whistle, we have got to make sure we are the team people have become accustomed to over the past three months.”
Although defeat in the West Midlands left eighth-placed Cherries 13 points adrift of the automatic promotion spots, Simon Francis insists the gap is not insurmountable.
Defender Francis told the Daily Echo: “If the run had to come to an end, I would rather it happened now so we can go again and, hopefully, start another one. There are a lot of games left and there is a long way to go. The play-offs are still easily within our reach, although the top two is what we are aiming for.
“We were disappointed with the performance at Walsall because our standards are so high and we don't expect to lose any game in this league. We want to be the best, we want to beat the best and, with the greatest respect to Walsall, we should be winning those games. We have got to look at ourselves and our performance and try to make things right at Hartlepool.”