Striker Sam Smith (right) has netted three times since joining Wrexham from Reading in January
Sam Smith struck a late winner as Wrexham rose above Wycombe Wanderers into second in League One in a contest that was delayed for more than 30 minutes because of a medical emergency in the crowd.
Fred Onyedinma and Daniel Udoh tested Arthur Okonkwo in the opening stages while Jay Rodriguez's header was easily dealt with at the other end following an even start to proceedings.
Onyedinma fired over from the edge of the Wrexham box in the latter stages of the first half as there was nothing to separate the sides at half-time.
Phil Parkinson's side created the clearest opening on 57 minutes, as January signing Smith intercepted a loose defensive header, although he could only prod his effort against the post.
Referee Ben Speedie then waved away claims from both sides for penalties in quick succession.
Play was halted in the 77th minute over a medical incident in the away section of the Adams Park crowd and both sets of players left the field.
Following a 35-minute stoppage, a supporter was taken to hospital in a "stable condition".
Players returned to the pitch to complete a 10-minute warm-up before the game resumed, with George Dobson clearing off his own line soon after the restart as Caleb Taylor appeared destined to score.
And the visitors responded in stunning fashion as Fletcher's header, following a Matty James shot, fell to Smith whose deflected strike beat Will Norris.
Okonkwo produced a fine save to keep out James Berry's effort as Mike Dodds' side pushed for a late equaliser.
But Wrexham held on to complete a first ever Football League double over Wycombe, inflicting only a second defeat in 17 home league matches on the Buckinghamshire side.
Victory lifts Wrexham up to second, three points clear of Wycombe, although the Chairboys have a game in hand over the Welsh side.
Wrexham boss Phil Parkinson said:
"After losing on Tuesday (at Reading), as much as I moaned about the ref, we could have done better.
"But if you take the last six away games, we've won five of them, that's an incredible return for us.
"Today we put it right. It was key that we're not going to over celebrate this because it's just three points, but it's a big win."
Wycombe Wanderers boss Mike Dodds told BBC Three Counties Radio:
"The disappointment from our point of view, these types of games are going to be decided by moments.
"I think it was one minute and 20 seconds from when they cleared the ball off the line to the ball being in the back of our net.
"That's how brutal it can be at the top, it's a harsh lesson for us."
