Following the high-scoring loss to the Packers, the Vikings, continuing with Christian Ponder as their quarterback, travel to Arlington, Texas to face the Dallas Cowboys. The first quarter was all field goals, as Dallas scored first with a 41-yarder by Dan Bailey, followed by a 23-yarder for the Vikings by Blair Walsh. In the second quarter, Bailey made another field goal from 44 yards to put the Cowboys up by 3, but the Vikings took a 10-6 lead into halftime, capping the ensuing 79-yard drive with a 6-yard run by Ponder. After the half, Cowboy quarterback Tony Romo completed two consecutive 26-yard passes to tight end Jason Witten to give them an early touchdown and restore their three-point lead. On the very next play from scrimmage, Ponder fumbled the ball as he was sacked in the end zone, and the Cowboys' Nick Hayden recovered it for a touchdown, meaning the Vikings went from 10-6 up to 20-10 down in the space of two scrimmage plays. The Vikings responded immediately with a quick, six-play drive, culminating with a 31-yard pass from Ponder to Kyle Rudolph to cut the Cowboys' lead back to three points. After a series of punts going into the fourth quarter, Adrian Peterson scored for the Vikings with an 11-yard run with almost six minutes to go, but Walsh pushed the extra point kick wide right, giving the Vikings a three-point lead over the Cowboys. Vikings cornerback A. J. Jefferson intercepted Romo on the Cowboys' ensuing drive, putting the Vikings in a position to potentially take over the game, but the offense went three-and-out and was forced to punt. The Cowboys progressed downfield quickly, never faced with a third down, and scored with a 7-yard touchdown pass from Romo to Dwayne Harris, the third time the Vikings had given up a game-winning score in 2013. With less than 30 seconds to play, but they were unable to make any significant territorial gains and Ponder's last-second hail mary fell short, giving the Cowboys a 27-23 win.
Question: How many points were the Vikings leading by at the end of the first half?
Answer: 4