Leipzig into top four as Simons and Openda slay Cologne
Simons produced yet another masterclass as Leipzig's attacking fulcrum in midfield while showcasing his understanding with fellow summer arrival Openda, who lifted his league goal tally to 19 this season.
Simons, who laid on two goals in a 6-0 procession when these teams met earlier in the season, now has 11 assists and seven goals in 25 games this season.
Simons joined Leipzig on a season-long loan in summer from parent club Paris Saint-Germain.
Leipzig have been increasingly reliant on the Dutchman this season, with coach Marco Rose saying this week he was "very optimistic" the 20-year-old would stay beyond the season.
Leipzig defender David Raum, who was named in Julian Nagelsmann's Germany squad on Thursday, told DAZN: "Of course it was fun in the end, but it was hard work.
"We didn't take our chances in the first half but in the second half we did -- and you can see what potential we have when we do."
The three points could prove crucial as Leipzig duke it out with Dortmund for the final Champions League spot.
Dortmund, now two points behind Leipzig, can retake their lead with a win when they host sixth-placed Eintracht Frankfurt on Sunday.
"A very good away performance. We scored some nice goals, some very nice goals," said Rose.
Fresh from winning two in a row for the first time this season, Leipzig brought the energy early and hit the lead after 15 minutes through Simons.
Simons finished off a sublime short passing move, with Dani Olmo laying the ball onto Benjamin Sesko who found the goalscorer.
Cologne hit back just three minutes later when Sargis Adamyan turned in a corner at the far post.
Openda's 26th-minute strike was ruled out for offside but the Belgian broke through midway through the second half, tapping in a perfect Simons pass.
Openda scored again just four minutes later, heading in a floating Raum chip for his 19th league goal of the season.
"At training sometimes he bangs them over the fence and into the forest but today he put it in perfectly," Raum said after the match.
Amadou Haidara blasted in a low shot to add a fourth with 20 minutes remaining before Yussuf Poulsen, subbed on for Openda, added a fifth.
Cologne's loss, their 14th in 26 games this season, leaves them in the relegation play-off spot and seven points from safety with eight games remaining.