Chris Wilder’s return to the Kassam Stadium was ruined by a late Alex MacDonald strike as missed chances cost Cobblers in a 1-1 draw against Oxford United.
Wilder, who left Oxford for Northampton in January last year, looked set to celebrate a sweet success after Ivan Toney’s first-half free-kick gave his team the lead.
But MacDonald made the away side pay as he fired past debutant goalkeeper Shwan Jalal in injury time to secure a share of the spoils.
Cobblers had created plenty of opportunities against a stagnant home team, who were booed off by their fans at the break.
But the men in yellow finally had something to cheer late on, leaving Wilder and his men disappointed at the end of an evening which they dominated.
One piece of good news came in the form of Marc Richards, who got his first game time since suffering an Achilles tear early last month.
The striker had been named on the bench and came on for the final 15 minutes, but it was one of the players filling the void his absence had left who had the first Cobblers effort.
Toney, who was to be a key player for the Cobblers, hit a sweetly-struck volley that was deflected wide.
The resulting corner saw John-Joe O’Toole fizz a header past the far post before Josh Ruffels fired high over the bar at the other end.
Aside from that wayward effort, Oxford were offering little, while Cobblers’ threat was coming at set pieces, with Lee Collins becoming the latest player to head wide.
O’Toole then had a shot blocked by Johnny Mullins before Zander Diamond, climbing high at the back post, failed to hit the target.
The natives were growing restless and Cobblers soon got the goal their good play had merited as Toney’s free-kick bounced over the diving Jamie Ashdown and into the net.
Ruffels tried to respond with a drive that was deflected into the arms of Jalal, but the home side had offered little during a first half controlled by the Cobblers.
Oxford were lucky not to concede again early in the second half as O’Toole’s ball across the box almost found Toney.
There were finally signs of life in the Cobblers area soon after as right-back Sam Long sent the ball forward for Danny Hylton, who fired wide with only Jalal to beat.
Toney then turned sharply at the other end, curling his effort just past the post, before Hylton’s strike from a Kemar Roofe cut-back was deflected wide.
Joel Byrom was wasteful when well placed in the Oxford area as his shot sailed over, while Diego De Girolamo almost connected with a teasing cross soon after.
The Cobblers were desperate to add the second goal they deserved and they continually hassled and harried the home side, who were making mistakes in possession.
But there was still a fear that Oxford would land a sucker punch and when Jalal came charging out to try to gather a free-kick, panic set in.
Long found himself well positioned, but with the net gaping, he blazed the ball into the home fans behind the goal.
Cobblers then brought on Richards for Toney, who had earned his standing ovation, in a bid to make the game safe and the striker immediately had an effort blocked.
But Oxford were about to get their act together, with the fourth official’s signalling of four minutes of added time sparking them into life.
Jalal rushed out to punch a ball clear, but when it came back into the box, MacDonald finished low across the keeper to secure a draw.
Oxford United: Ashdown, Skarz, Mullins, Wright (c), Long, O’Dowda (Rose 62), Collins (MacDonald 76), Roofe, Ruffels, Vassell (Roberts 69), Hylton.
Subs not used: Clarke, Ashby, Humphreys, Dunkley.
Cobblers: Jalal, Moloney, Collins (c), Cresswell, Horwood, D’Ath, Byrom, O’Toole, Holmes (Tozer 87), De Girolamo (Hackett 74), Toney (Richards 79).
Subs not used: Duke, Carter, Gray, Perry.
Referee: Brendan Malone
Attendance: 4,836 (610 Cobblers fans)