Mertens broke Panama's resolve with a wonderful volley

Despite some ropey defending at times, the Panamanians held firm during the first 45 against their illustrious opponents, but when the breakthrough came it was via a piece of real quality from the 'Red Devils' star.

Roman Torres headed away a cross form the right, with Armando Cooper and Eden Hazard rising in a bid to win the loose ball. Neither party could get telling contact on it, the ball dropping perfectly for Mertens to unleash a volley with the outside of his right foot from an angle, with the ball arching into the far corner of Jaime Penedo's net.

There was nothing the experience Panama goalkeeper could go as Mertens bagged his 15th international goal in his 70th outing.

Given the wealth of talent available to Roberto Martinez, the Belgium boss will be concerned at the lack of gilt-edged chances created in open play against such lowly opposition.