(Reuters) - Republicans are headed for big gains in the Senate in the November 2 election, but winning a majority will still be a difficult goal, according to poll averages compiled by the website Real Clear Politics.
Republicans must sweep nearly all the competitive races to pick up the 10 seats needed for a majority in the Senate, where Democrats now hold a 59-41 edge.
The polls show Republicans leading in races that could give them a net gain of eight seats, which would leave Democrats with a 51-49 edge. Republicans are close in several other races.
A Republican moved ahead on Tuesday in another state where Democrats thought they would cruise to victory. Republican John Raese has a 2.5 percentage point lead over Democratic Governor Joe Manchin in the West Virginia race to replace the late Robert Byrd
A Reuters/Ipsos poll in Ohio showed on Tuesday Republican Rob Portman with a commanding 13-point lead over Democratic rival Lee Fisher in the Senate race.
In the House of Representatives, the Real Clear Politics averages show Republicans with a slight edge. Republicans lead with 207 seats to 191 for Democrats, with 37 contests considered toss-ups in the battle for a 218-seat majority.
Republicans must pick up 39 Democratic seats to claim House control in November.
Here is a look at the Real Clear Politics poll averages in the most competitive Senate races, with the party currently holding the seat in parenthesis.
* California (Democrat) - Democratic Senator Barbara Boxer leads Republican challenger Carly Fiorina by 6 percentage points.
* Colorado (Democrat) - Republican Ken Buck leads Democratic Senator Michael Bennet by 2 percentage points.
* Connecticut (Democrat) - Democrat Richard Blumenthal leads Republican Linda McMahon by 4 percentage points in a race that is getting tighter.
* Delaware (Democrat) - Democrat Chris Coons leads Republican Christine O‘Donnell by 15.7 percentage points.
* Florida (Republican) - Republican Marco Rubio leads independent Charlie Crist by 10.6 percentage points, with Democrat Kendrick Meek trailing.
* Illinois (Democrat) - Republican Mark Kirk leads Democrat Alexi Giannoulias by 1.6 percentage points.
* Kentucky (Republican) - Republican Rand Paul leads Democrat Jack Conway by 5.8 percentage points in a tightening race.
* Missouri (Republican) - Republican Roy Blunt leads Democrat Robin Carnahan by 5.5 percentage points.
* Nevada (Democrat) - Democratic Senate Leader Harry Reid leads Republican challenger Sharron Angle by 1 percentage point.
* New Hampshire (Republican) - Republican Kelly Ayotte leads Democrat Paul Hodes by 8.3 percentage points.
* Ohio (Republican) - Republican Rob Portman leads Democrat Lee Fisher by 13.6 percentage points.
* Pennsylvania (Democrat) - Republican Pat Toomey leads Democrat Joe Sestak by 6.5 percentage points.
* Washington (Democrat) - Democratic Senator Patty Murray has widened her lead over Republican Dino Rossi to 5.3 percentage points.
* Wisconsin (Democrat) - Republican challenger Ron Johnson leads Democratic Senator Russ Feingold by 8.4 percentage points.
Republicans also hold commanding leads in three Democratic-held states -- Arkansas, Indiana and North Dakota. (Compiled by John Whitesides; Editing by Philip Barbara)