It seemed inevitable that the Colorado Rapids would need to morph into a more defensive-minded club when leading scoring Conor Casey tore his Achilles' tendon last month.

Thanks to Sanna Nyassi, they've turned into an offensive force.

Casey's replacement has four goals in three games, a surge the Rapids would love to see continue Friday night as they try to avenge an ugly June loss to the Columbus Crew.

Casey had scored in four straight matches and six of seven overall before rupturing his Achilles' on July 16 at Seattle, but his teammates weren't exactly chipping in. Just two of Colorado's eight goals in that seven-match stretch came from anyone other than the club's all-time leading scorer.

Instead of crumbling offensively without Casey, the Rapids (8-6-10) have kept pushing forward with much better results. They've scored eight goals in the three games since, winning twice and drawing once.

Nyassi had a hat trick in a 4-1 win July 20 against New York - his first three goals of the season - and scored again just before halftime last Friday in Philadelphia, the eventual game-winner in a 2-1 victory.

"It's crazy. We lost our most prolific striker who time and time again has delivered for this club," captain Pablo Mastroeni, who also scored against the Union, told the league's official website. "Conor's injury provides someone else with an opportunity and it was (head coach Gary Smith's) ability to assess the situation and give Sanna the chance, and he has stolen it and run with it."

Nyassi still has striker Omar Cummings to work with, and though Cummings has only two goals after scoring 14 last year, he's assisted on all four of Nyassi's goals.

"The pair of them are getting involved in moments that change the course of events," Smith said. "Those moments are what everybody is striving for, those flashes of brilliance."

Smith would certainly love to see a few more against Columbus (9-6-7), which has a two-point lead in the Eastern Conference despite having the same number of points as the fourth-place Rapids.

The Crew certainly looked like a top-tier club when they hosted Colorado on June 26. Casey got the Rapids on the board in the fifth minute but was sent off in the 29th as Columbus turned the tables in a 4-1 win that served as a small measure of revenge against the club that knocked it out of the 2010 postseason.

The Crew have scored only four goals in six matches since, but two of those came in a very impressive win Saturday. Eddie Gaven and Tommy Heinemann scored in the first 10 minutes and Columbus held on to stun Real Salt Lake 2-0, becoming just the third visiting team to beat RSL in its past 43 games.

"Obviously beating Salt Lake, not a lot of teams come in here and win, says a lot but by no means does it say our season is in the bag or we've done our job," Heinemann said.

"There's still a lot of ball to be played."