Accrington Stanley moved up to second in League Two with a 2-1 win at Hartlepool United.
Seamus Conneely gave Stanley an early lead with a firmly struck volley after just three minutes.
Hartlepool levelled through Rakish Bingham’s header at the back post before Tarique Fosu-Mensah slotted home after Josh Windass had hit a post.
Stanley had started the day in fourth but have now moved ahead of both Oxford and Bristol Rovers, as well as moving nine points clear of Pompey, who have one game in hand, in sixth.
Oxford’s promotion push continued to stutter as they could only draw 1-1 at Newport.
The point means Newport are pretty much safe from relegation with York needing a miracle to survive.
Meanwhile, Bristol Rovers were held to a 0-0 draw at Stevenage, while Plymouth built on Saturday’s win at Fratton Park to move to fourth, level on points with Oxford.
Former Pompey striker Jake Jervis scored twice as the Pilgrims won 3-1 at Leyton Orient.
AFC Wimbledon won 2-0 at Dagenham and are now just one point behind Pompey.
Lyle Taylor scored both the goals.
Wycombe are four points outside the play-off positions in eighth place after they could only draw 0-0 at home to lowly Yeovil.
Cambridge won 7-0 against Morecambe, while champions Northampton beat Crawley 2-1.
Barnet beat Notts County 3-1, Luton won 2-1 at Carlisle, and Mansfield earned a 3-2 victory at Exeter.