The Philadelphia Union can thank newcomer Roland Alberg for retaining the top spot in the Eastern Conference after winning a thrilling match against the Chicago Fire, 4-3.

Alberg netted a hat trick in just his fifth start since coming to MLS this past offseason. Union coach Jim Curtin certainly would have enjoyed the win over the club where he spent the majority of his playing career with, especially after a slow start to the contest.

David Accam gave the Fire an early lead, before Alberg notched an assist for an unfortunate own goal after his fierce shot hit both posts before taking a final touch off Jonathan Campbell for the equalizer.

The Dutchman followed up that effort with three straight goals, the first coming barely a minute after Campbell's own goal, adding a second in first-half stoppage time, before completing the hat trick in the 56th minute.

But the Fire were not done and ensured a nervy ending for Philadelphia, as Razvan Cocis reduced the deficit to two before Khalyu Thiam had Chicago back in within a shout with 10 minutes remaining, but the visitors eventually came up short.

Elsewhere, a late Jordan Allen strike ensured Real Salt Lake kept the three points in its home clash against the New York Red Bulls.

The Red Bulls took an early lead through defender Gideon Baah, but it would not last as Yura Movsisyan leveled the score after 65 minutes, before Allen won the game in the 87th minute with a deflected strike.

Meanwhile, the LA Galaxy and Colorado Rapids played out a scoreless draw in Los Angeles.

Despite the dropped points, the Rapids remain four points clear of second-place FC Dallas atop the Western Conference standings, while they also have a game in hand on their nearest rivals.

The Galaxy move up to fourth on 22 points.