Gills, five points clear at the start of play, could do no better than a goalless draw at Oxford, while Vale managed a 2-0 win.
Tom Pope was their match-winner, notching in the 40th and 62nd minutes.
Fleetwood remained in third spot after salvaging a 2-2 draw at Cheltenham.
David Ball gave the visitors the lead after 32 minutes but Jeff Goulding and Sido Jombati scored in 10 second-half minutes to turn the score on its head. However, Junior Brown saved a point for Fleetwood in injury time before Alan Bennett was handed a late red card.
Rochdale leapt from ninth to fifth with a 3-2 win at Accrington, Jason Kennedy with the winner seven minutes from time.
George Donnelly scored in the first minute for Dale and Ashley Grimes added a second from the penalty spot but Piero Mingoia and Romuald Boco netted either side of half-time in reply.
Bottom side Barnet picked up just their third point of the season with a 2-2 draw at Southend.
Goals from Rickie Holmes (54) and Jake Hyde (65) had raised hopes of an even better result but a Freddy Eastwood penalty and a Kevan Hurst effort with six minutes left put paid to that.
Dagenham edged an entertaining clash with visiting Bradford 4-3.
Billy Bingham, Michael Spillane and Luke Wilkinson gave the home team a three-goal cushion before a Nakhi Wells brace gave the Bantams hope.
Dwight Gayle grabbed the Daggers' fourth before Alan Connell rounded out the scoring for Bradford.
Chesterfield were 1-0 victors over Aldershot, thanks to Chris Atkinson's goal in the 76th minute.
Northampton lost Anthony Charles to a 24th-minute red card and could not overcome the disadvantage as they went down 3-1 at Bristol Rovers.
Tom Eaves (53), Garry Kenneth (57) and Oliver Norburn (84) all took advantage to score, with Adebayo Akinfenwa on hand with a consolation.
AFC Wimbledon turned one point into three when Rashid Yussuff snatched a last-gasp winner in a 2-1 success over Plymouth.
Byron Harrison's 13th-minute strike looked to be enough for the visitors only for Argyle to hit back with just a minute to go via Rhys Griffiths, though Yussuff still had time to win it.
Wycombe defeated Torquay 2-1 after goals from Gary Doherty and Josh Scowen negated Rene Howe's effort.
York versus Rotherham and Morecambe against Burton Albion both finished goalless.
adidas has added some color to the Predator line with this new colorway. Released on May 17. Be the first to own a pair.
The adidas Nitrocharge is the most talked about new cleat in years. It was released on May 15 and will take your pitch by storm.
Bayern Munich are kings of Germany and hope to be crowned kings of Europe at Wembley later this month!
The push for more color on their cleats, adidas has added the infrared colorway to the adiZero f50 Line.
The Juventus jersey for the 2013/14 was released earlier this week. Be the first to wear the colors of the Old Lady.
Chelsea won the Europa League on Wednesday. The Blues defeated Benfica 2-1 on injury time goal from Ivanovic.
One of the top soccer cleats for control the Nike CTR360 will not let you down on the field in tight spaces.
Ajax has released their away soccer jersey for the 2013/14 season. Get in the Gear.
The new PUMA evoSPEED 1.2 FG. A great new soccer cleat with classic look and first time for PUMA to be on the cleat.
Borussia Dortmund hears Wembley Calling and are headed to London for the Champions League final.