Southampton 0-5 Arsenal: Theo Walcott nets hat-trick as Gunners reach FA Cup fifth round

Theo Walcott netted a hat-trick against his former club as Arsenal thrashed Southampton 5-0 in the FA Cup fourth round at St Mary's.

Both managers made 10 changes to their line-ups, but the Gunners' understudies were a class above and were in front in the 15th minute thanks to a fine finish from Danny Welbeck, who then slotted home superbly to double the Gunners' lead seven minutes later.

With Arsene Wenger watching on from the stands as he began his four-match touchline ban, Walcott prodded home a third 35 minutes in to put the visitors out of sight before half-time.

Both teams took their foot off the gas in the second half, but there was still time for Walcott to net a fifth treble for the Gunners after finishing off fine passing moves in the 69th and 84th minutes, as Arsenal moved a step closer to a third FA Cup triumph in four seasons.

Arsenal dominated possession right from the off, with Walcott and Hector Bellerin combining well down the right, but it was an incisive move through the middle that saw the Gunners break the deadlock.

With the ball drilled into his feet, Lucas Perez used the pace of the pass and guided the ball around the corner into Welbeck's path, who took a touch out of his feet before delightfully lofting the ball over rookie Saints stopper Harry Lewis.

Seven minutes later it was two. Lewis again was helpless as Welbeck rounded the goalkeeper before slotting the ball home. The assist this time came via the boot of Alex Oxlade-Chamberlain, whose long ball over the top was perfect.

Saints then twice went close to getting themselves back in it, but Pierre-Emile Hojbjerg fired over from a good position, before Shane Long was denied by a fine David Ospina save from the angle.

Those missed chances proved costly, as Walcott made it three. Welbeck this time turned provider as he pulled the ball back for his England team-mate, as Walcott beat a casual Jack Stephens to the ball to prod home.

After the break, Southampton manager Claude Puel made some changes to try and influence proceedings, but even the injection of Nathan Redmond and Dusan Tadic couldn't trouble a comfortable Arsenal.

Instead it was the visitors who made the result all the more impressive through Walcott. The fourth goal was laid on a plate by substitute Alexis Sanchez, as the Chile international got to the byline before pulling the ball back for Walcott to stroke home.

Then, Sanchez again turned provider as he broke clear, turned back inside before squaring for the onrushing Walcott to net his 99th goal for the Gunners, and ensure the match ball will be heading back to London with him.