Spalding battled to an impressive victory at third-placed Ashbourne although a try just five minutes from time denied them the bonus point.
Nevertheless, victory against a side who had twice beaten them this season leaves them in pole position for a home fixture in the play-offs.
Niall Thomson’s side lie second in Midlands Two East (North) and with table-toppers Belgrave cruising to a 43-8 victory over Nottingham Casuals it means Spalding will almost certainly have to settle for second place.
Unless Belgrave slip up in their final match at fourth-placed Oakham, Spalding will face Midlands Two East (South) runners-up Newbold on Avon in the play-offs and whoever has the most points will be at home.
The four points Thomson’s men picked up on Saturday leaves them on 88 while Newbold on Avon have 85 so victory at home to Bakewell Mannerians is crucial if Spalding want to host the play-off fixture on April 26.
Spalding went ahead after five minutes when the home side were penalised for going over the top and James West’s kick went clean between the posts.
Ashbourne were then awarded a penalty of their own on the 22-metre line after 12 minutes and it was converted to make the scores level.
Spalding winger Hamish Munroe received a cut to his head in the build-up to the penalty and was replaced by Ed Booth but it wasn’t long before the visitors regained the lead when Tom Duerden crashed over for a try on 15 minutes.
A good conversion from West made it 10-3 and he stretched the advantage 10 minutes later with a penalty.
Full-back Adam McHugh went over just before the break and West again converted to make it 20-3 but the hosts reduced the arrears with the last play of the half with a penalty.
Spalding made some changes with Munroe returning to the pitch and taking his place on the wing with McHugh moved to centre and Booth taking over the full-back position with George Brown coming off.
Spalding were soon back on the attack with Booth making good ground into the home defence.
The ball went back across the field before a grub kick through the home defence saw Wes Cope racing through to touch down but it was not to be to the satisfaction of the referee and Ashbourne cleared.
Ashbourne quickly moved the ball across field and caught out Spalding who were were outnumbered by the home side who took advantage to score in the left corner.
A failed conversion though left the score at 20-11 with 35 minutes to play.
Spalding increased the lead 10 minutes later when they were awarded a penalty on the 22 metre line and West punished the home side to make it 23-11.
The final quarter of the match saw the home side using the advantage of the wind and the slope as they put pressure on the Spalding defence.
The visitors held out until five minutes from time when Ashbourne drove for the line and scored wide out.
Again they failed with their conversion but with their spirits raised from the try they pressed hard in the final few minutes.
They were awarded a penalty in the closing stages but their kicker could not add any more points and it remained 23-16.
The final whistle came to the relief of the visitors who were far from disappointed at not picking up the bonus point.
Skipper Harry Sharman said: “We knew it would be a difficult place to go and as they had beaten us twice already this season, we knew we would have to play well to get the win.
“We started really well and opened up a nice lead but they came back at us and were relieved to hold on as it was a fierce contest.
“Now we really need to win on Saturday and ensure a home match for the play-offs.”
Spalding RFC: Harry Sharman (captain), Pete Waudby, Wes Cope, Alex Ioannou, Andy Hoyles, Tom Duerden, Ed Duerden, Harry Brown, Rob Lucas, James West, Hamish Munroe, George Brown, Ryan Chappell, Harry Harrison, Adam McHugh, Josh Caley, Tim Waltham, Ed Booth.