Birmingham City's impressive form continued as they thrashed Millwall 4-0 at St Andrew's, ending the Lions' unbeaten away record. The Blues' victory was their third in four matches, with Chris Davies' side moving up to ninth in the table. Paik Seung-ho scored his second goal in successive matches, with Demarai Gray netting just his second of the season on the stroke of half-time. Alex Cochrane added a third goal four minutes into the second half, and Jay Stansfield completed the rout with their fourth on 65 minutes. Birmingham were unchanged from Saturday's home win over Portsmouth, with on-loan Sunderland winger Patrick Roberts passed fit to start. Millwall made four changes following their 2-2 draw at Oxford United. The win was a testament to Birmingham City's hunger and relentlessness, with Davies praising his side's performance. Birmingham will take huge confidence into their game with third-placed Middlesbrough at the weekend. Millwall's defeat ended an impressive six-match unbeaten start on the road, with the Lions managing just two shots on target all evening. Chris Davies told BBC WM that his side had picked up from where they left off in the previous game, which was really pleasing. The Blues' head coach also praised his side's management of Millwall, who are a solid and seasoned team at this level. Birmingham City's victory was a significant one, with the Blues moving up the table and gaining momentum. The club's fans will be hoping that this form continues, with the Blues facing a tough test against Middlesbrough next. The match was played in very wet conditions, with both goalkeepers being tested in the opening 25 minutes. Millwall's Joe Cundle hit a thumping right-footed volley from the edge of the area, forcing Blues keeper James Beadle to palm it away. Stansfield then forced Millwall's Max Crocombe to save low to his left with a shot from the edge of the area. The Blues opened the scoring just a minute later, with Roberts sending a cross into the box that found Paik, who fired it home into the bottom right corner. Birmingham doubled their lead in the final minute of the first half, with a heavy touch from Millwall's former Blues defender Wes Harding gifting the ball to Stansfield. He exchanged passes on the edge of the box with German striker Marvin Ducksch before crossing for Gray to flick past a despairing Crocombe. The home side added a key third goal just four minutes into the second half, with Roberts again causing problems down the right and pulling it back for Tomoki Iwata. His cross was headed out but only as far as Blues full-back Cochrane, whose fierce volley from the edge of the area took a slight deflection on the way through. The influential Stansfield got his sixth goal of the league campaign when Iwata played a short pass to substitute Keshi Anderson, who found Stansfield just outside the box and he controlled a bobbling ball before shooting past Crocombe to seal the victory.