Sam Szmodics boosted Derby County's Championship play-off hopes with a first-half winner at Fratton Park that damaged Portsmouth's bid to avoid relegation.
Ipswich Town loanee Szmodics gave the visitors an early lead with a cool side-footed finish that found the bottom corner.
The Rams hit the woodwork twice in search of a second, with Patrick Agyemang having a first-half shot touched onto the post before Joe Ward crashed a free-kick onto the crossbar after the break.
Derby's third-choice goalkeeper Richard O'Donnell - who has stepped up in the absence of the injured Josh Vickers and number one Jacob Widell Zetterstrom, who has struggled with a mystery illness since January - made a fine save to keep Millenic Alli out in the 70th minute.
It helped to ensure the Rams ended a three-game losing run away from home with a victory that moves them within three points of the play-off spots.
Despite having 27 shots, nine of which were on target, John Mousinho's Pompey were limited to few real chances as they slumped to a fourth successive home defeat that leaves them just one point above the drop zone - although they have a game in hand on their rivals.
Derby boss John Eustace had to watch his side revive their faltering form on the road from a seat in the directors' box at Fratton Park, as he served a one-match touchline ban after being shown a third yellow card of the season in last week's defeat by Millwall.
Portsmouth's inability to deal with the first corner of the game from Derry Murkin teed Szmodics up for the Rams' early opener.
Jacob Brown's defensive header landed at the feet of the unmarked striker, who had time and space to control the ball before guiding the ball home.
It took a combination of fine goalkeeping and a touch of fortune from Nicolas Schmid to twice deny Derby from adding to their first-half advantage.
He did well to rush out and smother a dinked shot from Ben Brereton Diaz in the 19th minute, while the touch he got on Agyemang's fierce shot that beat him at the near post was enough to divert the ball onto the far post.
Seconds later, Derby's stand-in keeper O'Donnell showed why Eustace said he has "confidence" in the experienced 37-year-old to see out the season, as he denied Gus Caballero after Pompey raced away on the counter attack.
Pompey went on to dominate possession in the second half, but apart from O'Donnell getting down low to his left to prevent Alli from equalising, Derby's defence - led by the commitment of Matt Clarke and smarts of Murkin - kept them well contained.
Ward's curled free-kick that clattered the bar before that was the closest Derby came to increasing their margin of victory.
Image source, Shutterstock
