Belgium took 70 minutes to get going before substitute Marouane Fellaini powered in a header from a corner.
Algeria took a surprise lead early on after Tottenham Hotspur defender Jan Vertonghen brought down Sofiane Feghouli in the penalty area. That same man stepped up and put it cooly past Chelsea FC keeper Thibaut Cortois.
For the rest of the first half, Belgium played out a pretty dour affair and Algeria did well to frustrate them. A half-time change of Mertens for Chadli seemed to have no real effect at first and Algeria continued to look solid and again frustrate Belgium further.
The introduction of Fellaini in the 65th minute didn't go down particularly well with many fans remembering his nightmare first season at Old Trafford. However the Fellaini that stepped on the pitch was a Fellaini from the Everton FC days. Driving forward and being used as a target man, he started to cause all sorts of trouble.
Belgium finally got their breakthrough in the 70th minute when Fellaini headed home a corner and you could see the relief on the Belgium players faces. From this moment on Belgium looked to enjoy themselves and play with a lot more of a relaxed tone. They started to really pile the pressure on and took the lead through an effective counter attack.
The ball broke to Chelsea FC winger Eden Hazard who played through half-time substitute Mertens who smashed it home near post to give Belgium all 3 points.
Belgium will play their remaining games on the back of a win and feel less pressure now, whilst Algeria can take many positives and be quietly confident for their last two games.